BIOS Flashing FAQ
Updated June 26, 2002
This document is an "in-development"
FAQ provided as a reference only. Contributors to this document are welcome
to add or modify it as they wish as long as the modified document is sent
to me for updating. You can send your suggestions and/or modified document
to biosflashingfaq (at) setiri (dot) com.
Flashing the system BIOS or any other BIOS for that matter is a dangerous
operation. Performing a flash can render the system inoperable. Any modifications
done to a BIOS with or without the aid of this document is completely
up to the user. Neither I, the author, nor any other person contributing
to this document can be held accountable for any loss of data, or failure
of any flash procedure done.
is the BIOS and how does it work?
Inside every PC out there is
BIOS, which stands for Basic Input Output System. In a nutshell,
BIOS is software that interacts between a computers hardware and the operating
system and software applications. There are several types of BIOS's,
ranging from the motherboard ROM BIOS to adapter BIOS's such as video
BIOS, drive controller BIOS, network adapter BIOS, SCSI adapter BIOS,
etc... These BIOS's are the lowest level of software in a computer providing
a set of small programs or software routines that allow the hardware of
a computer to interact with the operating system by a set of standard
I hope to provide a through
understanding of how the BIOS works and leave you with a better understanding
of it's interworkings. At the same time, I hope to show how complex a
BIOS is in relation to it's relationship with the operating system and
the software applications you use everyday. Enjoy.
To get to the operating system,
a computer must first boot from the BIOS. The BIOS performs a number
of tasks when a computer is started. From initializing the microprocessor
to initializing and testing hardware to starting the operating system.
Starting a computer is not a simple task. It's a methodical process
that is performed every time power is applied to computer. Here
is a detailed description of the boot process. This process will
vary with different computers and different BIOS', but the overall goal
is the same. When you first turn on a computer the very first operation
performed by the CPU is to read the address space at FFFF:0000h. This
address space it reads from is only 16 bytes, which is not nearly enough
space to house the BIOS found on a motherboard. Instead, this location
contains a special instruction called a jump command (JMP) that tells
the processor where to go to find and read the actual BIOS into memory.
The process of the processor reading the jump instruction and redirection
to the actual BIOS is called the bootstrap or boot. So, when you apply
power, it's not the operating system that's working. It's the BIOS.
First, I want to get something
straight. The CMOS and the BIOS are two different things.
The BIOS refers to the firmware instructions that are located on the BIOS
ROM. CMOS refers to the low-power RAM that holds the system's setup
parameters. The BIOS reads the CMOS RAM into memory at boot up and
provides the setup routine that allows you to change the contents of CMOS,
but the CMOS RAM/RTC device is a totally different IC. The CMOS
holds the information provided by the BIOS. This is why you "lose"
the settings of a system when the battery dies or you clear the CMOS through
a jumper on the motherboard.
With today's high performance
32 bit operating systems, the BIOS becomes less used, but it is still
there, always interacting with the operating system. Disk access, for
example, is done through the operating system with 32-bit routines, whereas
the BIOS is using 16-bit routines. Although the BIOS provides VGA support,
Windows and other 32-bit operating systems use software device drivers
to work with the hardware. Early OS's, like DOS, worked with the
BIOS. DOS relied on the BIOS to perform most functions, like displaying
characters on the screen or sending output to the printer, reading input
from the keyboard and other essential tasks. These drivers, which operate
in protected mode(since they aren't written for real mode, they are able
to use memory above the 1MB barrier that real mode provides), allow for
several enhancements. They can access more memory, can be written
in 32-bit code for optimized execution and are not limited to the amount
of space available to their code. However, regardless of OS, whether it's
Windows 2000, Linux or DOS, the BIOS and the operating system still interact
with each other.
Here is a basic rundown of
what is happening:
is applied to the computer
When power is
applied to the system and all output voltages from the power supply are
good, the power supply will generate a power good signal which is received
by the motherboard timer. When the timer receives this signal, it
stops forcing a reset signal to the CPU and the CPU begins processing
first instruction performed by a CPU is to read the contents of a specific
memory address that is preprogrammed into the CPU. In the case of
x86 based processors, this address is FFFF:0000h. This is the last
16 bytes of memory at the end of the first megabyte of memory.
The code that the processor reads is actually a jump command (JMP) telling
the processor where to go in memory to read the BIOS ROM. This process
is traditionally referred to as the bootstrap, but now commonly referred
to as boot and has been broadened to include the entire initialization
process from applying power to the final stages of loading the operating
for Power On Self Test. It's a series of individual functions or
routines that perform various initialization and tests of the computers
hardware. BIOS starts with a series of tests of the motherboard
hardware. The CPU, math coprocessor, timer IC's, DMA controllers,
and IRQ controllers. The order in which these tests are performed varies
from motherboard to motherboard. Next, the BIOS will look for the presence
of video ROM between memory locations C000:000h and C780:000h. If
a video BIOS is found, It's contents will be tested with a checksum test.
If this test is successful, the BIOS will initialize the video adapter.
It will pass controller to the video BIOS, which will in turn initialize
itself and then assume controller once it's complete. At this point,
you should see things like a manufacturers logo from the video card manufacturer
video card description or the video card BIOS information. Next,
the BIOS will scan memory from C800:000h to DF800:000h in 2KB increments.
It's searching for any other ROM's that might be installed in the computer,
such as network adapter cards or SCSI adapter cards. If a adapter ROM
is found, it's contents are tested with a checksum test. If the
tests pass, the card is initialized. Controller will be passed to each
ROM for initialization then the system BIOS will resume controller after
each BIOS found is done initializing. If these tests fail, you should
see a error message displayed telling you "XXXX ROM Error".
The XXXX indicates the segment address where the faulty ROM was detected.
Next, BIOS will begin checking memory at 0000:0472h. This address
contains a flag which will tell the BIOS if the system is booting from
a cold boot or warm boot. A value of 1234h at this address tells
the BIOS that the system was started from a warm boot. This signature
value appears in Intel little endian format , that is, the
least significant byte comes first, they appear in memory as the sequence
3412. In the event of a warm boot, the BIOS will will skip the POST routines
remaining. If a cold start is indicated, the remaining POST routines
will be run. During the POST test, a single hexadecimal code will
be written to port 80h. Some other PC's send these codes to other
ports however. Compaq sends them to port 84h, IBM PS/2 model 25 and 30
send them to port 90h, model 20-286 send them to port 190h. Some EISA
machines with an Award BIOS send them to port 300h and system with the
MCA architecture send them to port 680h. Some early AT&T, Olivetti,
NCR and other AT Clones send them to the printer port at 3BC, 278h or
378h. This code will signify what is being tested at any given moment.
Typically, when the BIOS fails at some point, this code will tell
you what is failing.
for the Operating System
is complete and no errors found, the BIOS will begin searching for an
operating system. Typically, the BIOS will look for a DOS Volume
Boot Sector on the floppy drive. If no operating system is found,
it will search the next location, the hard drive C. If the floppy
drive (A), has a bootable floppy in it, the BIOS will load sector 1, head
0, cylinder 0 from the disk into memory starting at location 0000:7C00h.
The first program to load will be IO.SYS, then MSDOS.SYS. If the
floppy does not contain a DOS volume boot sector, then BIOS will next
search the computers hard drive for a master partition boot sector and
load it into memory at 0000:7C00h. There are some occasions in which
you will encounter problems with the proper loading of the Volume Boot
Sector. Below are some of those:
A. If the first byte of the Volume Boot Sector is less than 6h,
then you will receive a message similar to "Diskette boot record
B. If the IO.SYS or MSDOS.SYS are not the first two files in the
Volume Boot Sector, then you will see a message similar to "Non-system
disk or disk error".
C. If the Volume Boot Sector is corrupt or missing, you will get
a message similar to "Disk boot failure"
Once the BIOS has searched
for a bootable floppy device, it should turn it's attention to the next
boot device it's programmed to look for. The next device is typically
the hard drive, or C. Like a floppy drive, the BIOS will attempt
to load the Volume Boot Sector from sector 1, head 0, cylinder 0 from
the Master Boot Sector, or MBS, into memory starting at 0000:7C00h.
The BIOS will check the last two bytes of the MBS. They should be
55h and AAh respectively. If they are not, then you will receive
an error message similar to "No boot device available" and "System
initialization will halt". If they are correct, then the BIOS
will continue the loading process. At this point, the BIOS will
scan the MBR in search of any extended partitions. If any extended
partitions are identified, the original boot sector will search for a
boot indicator byte which indicates a active and bootable partition.
If it cannot find one, you will receive a message similar to "Invalid
At this, once a active partition
is found, the BIOS will search for a Volume Boot Sector on the bootable
partition and load the VBS into memory and test it. If the VBS is
not readable or corrupt, you will see a message similar to "Error
loading operating system". At the point, the BIOS will read
the last two bytes of the VBS. These bytes should be 55h and AAh
respectively. If they are not, then you will see a message similar
to "Missing operating system" It is at this point that
the BIOS will begin loading of the operating system.
should I do to prepare for flashing my BIOS?
Backup your system current
BIOS. Installing a new BIOS may introduce bugs into the system that may
create new system issues. Things like memory timing, CPU speed indicaters,
fan speed and power management issues as well. With both AMI and Award,
the utility has the ability to backup the current BIOS onto a floppy disk.
It's highly recommended that anyone performing a BIOS update perform this.
If you have a printer connected to the system you can print each setup
screen within the BIOS by using the "PrtScn" key on the keyboard.
This will give you a hard copy to check your settings against after the
flash takes place.
Make sure you have the correct
BIOS upgrade. If you have an upgrade for another motherboard, even if
the motherboard is in the same series, just a different model, chances
are pretty good you'll render the motherboard unusable. ONLY UPGRADE A
BIOS WITH A NEWER BIOS THAT IS DESIGNED FOR THE SPECIFIC MOTHERBOARD IN
Make sure you have a thoroughly
tested floppy disk AND drive in place before using them to flash the BIOS.
In the event of a CRC error during the flash, you will most likely have
to replace the CMOS. A costly operation in terms of money and downtime.
If anything goes wrong with the disk or the drive during the flash, it
will most likely toast your motherboard. Ensure that the drive your using
and the floppy disk itself are up to snuff. Test the disk thoroughly.
Write and read from it with large files. Perform a complete format of
the disk as well. If any bad sectors occur, replace the disk with another.
DON'T USE THE FLOPPY DISK IF ERRORS ARE FOUND ON IT!
When booting the system to
the floppy for flashing, ensure that the boot floppy itself has NO unneeded
drivers being installed. Things like CD-ROM drivers or mouse drivers will
reduce the amount of memory available for the flashing program to use.
If you run out of RAM during the flashing, your motherboard may be rendered
unusable. Always boot with boot disk that has no additional drivers. After
all, all you need is the floppy anyway. Enter
the BIOS setup and ensure that system and video BIOS caching is disabled
and all types of Shadow Memory are disabled.
do I flash a BIOS?
Flashing your motherboards
BIOS a fairly straight forward procedure. The required components are
the proper flashing utility and the proper data file that will be written
the CMOS. To accomplish this, your first stop is the web site of your
motherboard manufacturer and download the latest flashing utility and
BIOS update. There are other places to download the flashing utilities,
however, I recommend using the utility that comes with your latest bin
file or the one recommended by your motherboard manufacturer. With some
motherboards, the individual motherboard manufacturer uses their own proprietary
flashing utility. Make sure you always check your motherboard manufacturer's
website for any information and read the motherboard manual to find any
information related to this.
Ensure your using a newer floppy
disk and that your floppy drive is not causing any problems. If your floppy
drive is questionable, then replace it before performing the upgrade.
One bad CRC error during the flashing of the BIOS and it's toast. As for
the floppy, I highly recommend using a brand new one or at least a nearly
brand new one. Perform a complete format of the disk before using it to
ensure no problems are found with it. I also suggest that you don't use
a floppy disk that has any bad sectors or other problems with it.
Before flashing any BIOS you
should prepare the system for flashing. If your computer is overclocked
it is highly recommended that you set the CPU to run at the default speed.
Enter the BIOS setup and disable all forms of shadowing. This includes,
Video BIOS Cacheable and System BIOS Cacheable, which can be found within
the Chipset Features Setup. You should also disable any power management
features that are enabled. If you system has a setting within the BIOS
to protect the BIOS from flashing you will need to disable this as well.
Some motherboard have a jumper on them that can be set to protect the
BIOS from being flashed. This needs to be disabled as well if it is present.
For Award BIOS's:
For Award BIOS's, the flashing
procedure is fairly simple. It can be a little intimidating for those
who are unfamiliar to the command line though. Rest assured, it's really
not all that hard. After you have downloaded the latest BIOS and the flashing
utility, place those files on a floppy disk. You will want to have them
either on a floppy disk that is bootable or on a floppy disk separate
from the boot disk. In either case, your going to need a boot disk to
perform the flashing. To create a boot disk, insert a black floppy disk
into the drive. If your using Windows 9x, open My Computer and right click
on the A: drive. Select Format and ensure that the create system disk
is checked. For Windows 2000 users, your going to need a bootable disk
created elsewhere. Windows XP users can create a bootable floppy using
the same method as Windows 9x users. This creates a Windows ME boot disk.
Once you have a boot disk created and a copy of the flashing utility and
a copy of the latest BIOS update, your ready to flash the BIOS.
Boot to the bootable floppy.
Once you have booted the system to the command line ensure that the floppy
disk containing the flashing utility and the BIOS update is in the drive.
The next portion will vary from system to system. The flashing utility
and the BIOS update image will vary so the following is a general guideline
to working with the command line:
(a listing of the files located
on a: drive will be displayed)A:\>awdflash b1sv13.bin
(Runs the Award flashing utility
and directs it to the BIOS update file
Follow the onscreen instructions
for the flashing procedure. A word of caution at this point. DO NOT pull
the plug, press the reset button or otherwise interrupt the flashing procedure
once it has begun. Interruption of the flashing procedure WILL render
the system unbootable!
A method of flashing an Award
BIOS is to automate it. By creating a prepared bootdisk with the flashing
utility and the BIOS .bin file on it, you can create a bootable disk that
will flash the BIOS and perform other functions for you without having
you type anything. After you have created a bootable floppy, using you
favorite text editor, open the autoexec.bat file located on the floppy
disk. If one is not present then just save the file once you have created
it to the floppy as autoexec.bat. The following code will completely automate
the flashing procedure for you:
if exist oldbios.bin goto old
awdflash.exe newbios.bin oldbios.bin /py /sy /cc /cp /cd /sb /r
awdflash.exe oldbios.bin /py /sn /cc /cp /cd /sb /r
The awdflash.exe is the name
of the flashing program you are using. The newbios.bin is the name of
the bios image you downloaded for you motherboard. The oldbios.bin file
is the name of the bios you choose to save the old bios (your current
BIOS) onto floppy as. IF your BIOS flash fails, the old BIOS is in backed
up in oldbios.bin. You can just reboot with that floppy again and the
process of flashing the bios to the old version is automatic. As long
as the oldbios.bin is present on the floppy, it will get flashed to the
BIOS. After flashing the BIOS to a newer version remember to remove the
floppy from the drive. The process of flashing the BIOS is automatic,
so if you leave the floppy in the drive it will flash the BIOS again.
The following are the command
line switches for the Award flashing utility. You can use these in conjunction
with the flashing utility to help automate the flashing procedure. For
AWDFLASH xxxx.BIN /py/sn/cc
Would run the flashing utility
and tell the utility to perform the flash (/py), do not save the current
BIOS into a backup file (/sn), and clear the CMOS after performing the
flash (/cc). After flashing any BIOS, either Award, AMI, Phoenix, or any
other motherboard BIOS, always clear the CMOS. The values that are current
saved in the CMOS may not match the setup programs new procedures. If
the BIOS update installed any new instructions or set up new values for
any existing procedures, these values won't match what is expected. For
this reason, you should ALWAYS clear the BIOS after flashing it and reconfigure
the BIOS after clearing it.
/? - Help. Before you start
working with Award Flash Memory Writer, it is advisable to use this key
and to study carefully all the opportunities of this software.
/Py or /Pn - stands for answering
"yes" (Y) or "no" (N) to the request concerning the BIOS reflashing. By
means of /Pn you can ban FlashROM reprogramming. This option enables you
to save the current version of the BIOS or to get its checksum without
updating your BIOS. A backup copy will help you to restore the previous
version of the BIOS. By default /Py mode is set.
/Sy or /Sn - stands for answering
"yes" (Y) or "no" (N) to the request about saving the previous version
of the BIOS. By default /Py mode is set again. In this case before reprogramming
the FlashROM microchip you'll need to confirm saving by this request:
Do You Want To Save BIOS (Y/N)
/Sn is recommended to use for
*.bat-files in case of automatic BIOS reflashing in systems without a
/CC - to clear CMOS after reflashing.
This option comes in handy when there is a risk that the data arrays created
by new BIOS version in CMOS may differ from those former ones. If so,
then you are likely to have troubles with the mainboard startup. Clearing
CMOS will let you avoid searching for Clear CMOS jumper on the board,
which is really helpful if it isn't accompanied with a proper manual or
is simply hard to access.
/CP - stands for clearing PnP
(ESCD) Data matrix after BIOS reflashing. The information about PnP devices
is stored in ESCD. The key /CP is an equivalent to Reset Configuration
Data in PnP/PCI Configuration CMOS Setup. It makes sense to use /CP if
you skip several versions of BIOS or if you have installed new PnP cards.
If you don not update the ESCD, your board may suffer some startup problems.
/CD - stands for clearing DMI
Data pool after reprogramming. Literally, DMI is a data base, containing
all the information on the system as a whole. Clearing it may be fruitful
in the above mentioned situations with /CP and /CC keys, as well as if
some of the system components have been changed.
/SB - stands for no BootBlock
reflashing. The BootBlock is the first unit to be addressed by startup
and it is hardly ever changed. If the board manufacturer gives no other
recommendations, there is no need to reflash BootBlock. In particular,
if the BIOS reflashing fails, it may become impossible to restore the
BIOS via software. On some mainboards there is a BootBlock Protection
jumper. If protection is set, either you won't be able to reflash the
BIOS without /SB at all or the system will face verification errors.
- This setting has NOT been confirmed to
work. It may or may not work on your motherboard. Use with caution.
Thanks for the input Tmod.
/SD - stands for saving the
data of DMI pool in a file. Part of DMI can be saved to be used by the
software in future. Even though this key stands in the list, which is
shown by /?, using it will bring no result. This key simply doesn't work.
/R - stands for the system
reset after reflashing. It lets you have your computer restarted automatically
as soon as you finish updating FlashROM. The option is useful for working
through a *.bat-file.
/Tiny - stands for using less
RAM. Without the /Tiny key, AwardFlash utility tries to put the entire
BIOS file, which is intended for further reflashing, into RAM. Still,
if have taken all the precautions but anyway you see a message saying
"Insufficient Memory" during the BIOS reflashing procedure, then the key
/Tiny should be used. It will make the data from the BIOS file loaded
and reflashed in portions.
/E - stands for returning to
DOS after BIOS reflashing. For instance, you may need it to make sure
that the previous version of the BIOS is saved.
/F - stands for reprogramming
by means of the system BIOS. Most contemporary BIOS's feature the procedure
of FlashROM reprogramming. The key /F enables AwardFlash to reprogram
FlashROM with the algorithms of the current BIOS version. If a mainboard
peculiarities do not allow applying AwardFlash Writer algorithms, you
should use the key /F.
/LD - stands for clearing CMOS
after reflashing and not showing the message "Press F1 to continue or
DEL to setup". Unlike /CC, this key lets you avoid this message by the
following startup after clearing CMOS, provided you have set the properties
/CKS - stands for showing the
checksum of XXXXh file. The checksum is shown in hexadecimal representation.
This option is advised to be used with the verification key.
/CKSxxxx - stands for comparing
the checksum of the file with XXXXh. If the checksums are different, you'll
see the message "The program file's part number does not match with your
system!". As a rule, XXXXh for each BIOS update file is usually available
on the mainboard manufacturer's site
/WB - Updates the BIOS Boot
Block. This switch does not have to be used. The BIOS Boot Block will
get updated with the flashing of the BIOS.
- Thanks for the input Tmod
/CC = clear cmos data after
/CD = clear dmi data after
/CP = clear PnP (ESCD) data
/R = reset system after programming
/PY = program flash memory
Here are some additional command
line switches for the Award flashing program:
/? = show help menu
/SY = backup original BIOS
/SB = skip bootblock programming
/TINY = occupy lesser memory
/E = return to DOS when programming
/F = use flash routines in
original BIOS for flash programming
/LD = destroy cmos checksum
and no system halt for first reboot after programming
/CKSxxxx = compare binfile
checksum with xxxx
/CKS = show update binfile
/PN = no flash programming
/SN = no original BIOS backup
/SD = save dmi data to file
/WB = flashes the BIOS Boot
For AMI BIOS's:
should I update the BIOS? When should I upgrade my BIOS
[when is it really necessary, when is it just for "fun"]
Flashing a BIOS can be destructive
to the motherboard. Without a BIOS that is in proper working condition,
your computer will simply not work. The BIOS is actually what is used
to start your PC up, thus is a very important component to the operation
of any PC. Unless you are sure that your system requires an update and
that the update is going to fix any problem that you're experiencing,
then I would not recommend flashing the BIOS. Remember, if the flash fails,
then your system is NOT going to work. Further repair will be required
which could require monetary means to repair.
One thing I try to tell people
who are interested in doing flashing and/or doing BIOS modifications is
to pick up a few older motherboards at a local flea market or 2nd hand
store. Some place where you find some cheap used parts you don't mind
losing. This is a great way to learn/practice doing advanced things like
BIOS Moding without the worry of screwing up the new motherboard in your
main system. I would much rather lose a $10 board than a $200 one. The
salvation Army, Goodwill, or other second hand stores, as well as the
local hospice. I once found a Pentium 120MHz with mainboard and 128MB
of RAM still on it at a local hospice for $10 bucks. A deal and a half.
At the time the top of the line systems were PII 400's.
I boot the BIOS all it says is "BIOS checksum error, press F1 to continue...".
What should I do?
This is a result of the CMOS
losing the data that it was holding. There are a few ways that this can
be encountered. After flashing a BIOS, loss of battery power, an electrical
surge or bad power to name a few. Typically, this is a problem with the
CMOS battery running low. The result is usually discovered after the system
has been off for a few hours or longer. Replace the battery located on
If you just performed a flashing
of the BIOS, use the jumper on the motherboard to clear the CMOS. You
can also enter the BIOS and choose "Load BIOS Defaults".
do I clear the CMOS?
Clearing the CMOS can be done
a few ways. The most common way is to use the jumper on the motherboard.
This jumper has two settings. Normal and Clear. Moving the jumper to the
Clear setting will erase the settings stored in CMOS. It does not remove
the BIOS itself, only the user defined settings within the CMOS. When
you clear the CMOS you will most likely see the error message "CMOS Checksum
Error" on the next reboot. You can enter the BIOS setup at this point
or before and reconfigure the settings.
Another method is to remove
the CMOS battery from the system. Removing the battery is usually the
second method as it may take anywhere from 15 minutes to 8 hours in order
for the CMOS to loss the settings. Once the CMOS is clear, you should
know by the "BIOS checksum error, press F1 to continue ", or "CMOS Checksum
Error - Defaults Loaded" message at bootup.
You may also be able to clear
the CMOS in some cases by forcing a system configuration change. Changing
hardware, such as adding or removing a few SIMM's may cause a CMOS error
and allow you to proceed to the BIOS setup.
On a few systems it may be
possible to clear the CMOS by pressing the Ins key during the power up
of the system. Holding the Key down may clear the CMOS and restore the
defaults. This may or may not work on your system.
do I get a replacement BIOS chip? How
can I fix my BIOS chip after a bad upgrade?
There are a few ways to acquire
a replacement BIOS chip. Online resources include the following:
These places deal in replacement BIOS
chips for nearly all motherboards out there that contain an Award or
AMI BIOS. There are many more out there, but these are ones I personally
have heard about and have had people tell me they are reliable. As for
prices, you will have to contact them directly. It's my understanding
that each BIOS upgrade varies in price. I believe that the chip type
and motherboard type will determine the price. You can also buy your
own BIOS chip and program it yourself. However, a EEPROM programmer
is required for this. In the end, consider the cost of purchasing a
new chip for your motherboard versus the cost of purchasing a new motherboard.
You may be better off with a new motherboard over a new BIOS as the
new motherboard may offer newer features and offer a greater amount
of upgrades as well.
can I save my BIOS settings so that I can restore them later?
There are a few methods that
one can save the current settings. You can use the flashing utility to
save the current BIOS into a file or you can use printscreen to print
each of the BIOS setup screens. With this method, a parallel printer is
required and must be attached to the systems parallel port. A network
printer will not work, nor will a USB printer. Within each of the BIOS
setup screens, you can press the print screen key on the keyboard (this
is actually a BIOS service your calling) and the output of the current
screen will be sent to the printer port.
a flash utility and where do I get one?
hardtellin from Hardware
A flash utility is a small
program that is specifically designed to replace the computers BIOS programs
contained within the motherboards BIOS ROM. These flashing utility programs
are also designed to backup the current BIOS information into a file as
well as provide information on the current BIOS version. Newer versions
of these programs are developed to support newer flash ROM chips that
come out onto the market. In some cases however, these newer flashing
programs drop support for older flashable ROM chips. Usually those chips
that can be found on the late model 486's when the flashable ROM chips
first started to appear and the earlier Pentium motherboards.
In most cases, these flashing
programs can be downloaded via the Internet directly from your motherboard
manufacturer's website or from your computer manufacturer. In the case
of retail systems such as Hewlett Packard, Dell, and Compaq, a system
specific program may be required. This is especially the case of Compaq
systems. With nearly all Compaq systems, the BIOS is split into two parts.
Half of the BIOS is located on the motherboard and the other half is located
on the hard drive. For this reason, consult your user manual or online
documentation for complete details about your system.
can't I access my BIOS? I press DEL but nothing happens!
This is most likely because
the particular sequence to enter your systems BIOS is not by pressing
the Del key. There are several key combinations that work and each system
uses their own. When you first power up your computer, view the POST (Power
On Self Test) messages. Typically the message prompting you to enter the
BIOS setup will be displayed soon after the memory check is completed.
Within this message the proper key sequence will be displayed. If you
own an HP, Dell, Gateway or other manufacturer, a "splash" screen may
be present that hides the POST messages. You can bypass this by pressing
the Esc or Tab keys to view the POST messages.
Acer: - Ctrl+Alt+Esc
ALR PC: (F2) or (Ctrl)(Alt)Esc)
AMI BIOS: (Del), (F1)
AST, Advantage, Award, Tandon:
- Ctrl + Alt + Esc
Award BIOS: (Del) or
Compaq: (F10) (do this
when the cursor is in the upper right corner of the screen blinking)
Dell: - F1 or Del.
Dell: - Some require
pressing reset twice
Dell: - Ctrl + Alt +
DTK BIOS: (Esc)
Gateway 2000: - F1
Hewlett Packard: - F1
IBM PS/2: (Ctrl)(Alt)(Ins)
IBM PS/2 with reference
partition: - Press Ins during boot
Some PS/2s, such as 75 and
90: - Ctrl Alt ?
Some PS/2s when pointer
at top right of screen: - Ctrl + Ins
NEC: - F2
Packard Bell: - F1 or
Phoenix BIOS: (F1),
(F2), or (Ctrl)(Alt)(Esc)
Phoenix BIOS: - Ctrl
Phoenix BIOS: - Ctrl
Phoenix BIOS: - Ctrl
Sharp Laptop 9020: -
Sony: (F3) while you
are starting the PC, then (F2) or (F1)
Tandon computers: -
Hold down the <Esc> key after turning on power
Tandon: - Ctrl + Shift
Toshiba Laptops: - Toshiba
Toshiba: - Press Esc
Toshiba, Phoenix, late model
PS/1 Value Point and 330s: - Press F1 during boot
Olivetti PC Pro: - Shift
Ctrl Alt + Num Pad Del
- Ctrl + Esc or Ctrl and Alt and +
Zenith: - Ctrl Alt Ins
NOTE: Some new motherboard
designs have a jumper on the motherboard that disables access to the BIOS.
In order to access the BIOS setup, this jumper will have to be disabled.
You cannot access the BIOS setup until this jumper has been disabled.
do I tell what version of the BIOS is currently installed on the motherboard?
For Tyan motherboards: TYN
[motherboard model] Vx.xx MM/DD/YY
For QDI motherboards:
P6I440BX BrillianX-1S/2K BIOS V1.2SLRC Jan.07,2000
does CAS Latency 2 and CAS Latency 3 mean?
What Is It?
Over the last three years or
so, memory manufacturers have been releasing new and faster memory modules
at an ever quicken pace. Some are updates of existing types, while others
are redesigns and still others are entirely new innovations. We've moved
quickly from FPM to EDO memory, and then on to SDRAM. Then SDRAM jumped
from its initial release at 66MHz to 100MHz and then to 133MHz. In the
last year we've seen Rambus DR DRAM, and most recently DDR DRAM memory.
Now, after having digested all of these changes and innovations, and all
the hype about "substantial speed increases", the memory manufacturers,
distributors and retailers have decided to bombard us with the technical
terms as to why their product is better then that of another company.
One such example has been the issue of CAS Latency. Recently, a whole
raft of resellers have been publishing comments that the CAS Latency on
their Brand X modules are a huge improvement over that of Brand Y modules
sold elsewhere. Unfortunately, none of them go quite far enough to explain
just what this means. Is CAS Latency an issue? Is it hype, or is it something
I should be careful about? What does it mean?
Maybe yes, and maybe no. We
know you don't like that answer, but the truth is that much of how CAS
Latency effects your computer depends upon the component make-up of your
computer, how you use it and the programs you use.
Although our review of Memory Speeds digs into these issues, let's take a quick
look at the issue of memory timing by itself. CAS Latency (CL)
is the ratio between column access time (tCAC)
and the clock cycle time (tCLK), rounded
to the next higher whole number. The formula is rather simple really,
divide the column access time by the clock cycle time, then raise the
result to the next whole number.
As an example, if the tCAC
is 20 nanoseconds and the tCLK is 10 nanoseconds
(a 100 Mhz system bus), then the CL would be 2. If tCAC
is 25 nanoseconds, then CL would be 3 since 25/10 = 2.5 (rounded
up to 3).
Okay, so what does all of this
mean? To understand that, we need to understand the meaning of a few other
memory timing terms. By the way, for clarity purposes, we will be referring
to a 100MHz system bus.
- RAS - Row Access Strobe
- CAS - Column Access Strobe
- tRCD -
The length of time between RAS and CAS access.
- tRP -
The length of time to switch between memory banks.
- tAC -
The length of time to prepare for output.
- tCAC -
The column access time
RAS and CAS normally
appear in technical manuals with an over-line as in RAS
In lay terms, data is transferred
from memory to the CPU as follows:
- The CPU sends a signal specifying the
memory row and bank that it wants to access via the RAS line.
- After a specific period of time (tRCD)
the CPU sends a signal on the CAS line, specifying the column it wants
- After tCAC
(column access time) the data moves to the output line, from where
it is transferred with the next clock tick.
- The CPU expects the data to appear
upon a specific clock tick after sending the request.
Since the clock cycle is the
inverse of the bus speed, it is defined for our purposes here as 10 nanoseconds.
On a 100 Mhz. bus, data transfer takes about 2 nanoseconds. According
to the PC 100 specification, tAC is 6 nanoseconds,
and it takes about 2 nanoseconds for the signal to stabilize.
6 nanoseconds (tAC)
+ 2 nanoseconds to stabilize = 8 nanoseconds
8 nanoseconds + 2 nanoseconds for transfer time = 10 nanoseconds = 1
Therefore, in burst mode, the
three data transfers after the first one that requires 50 nanoseconds,
data can be transferred in one clock cycle. SDRAM is a multi-bank architecture,
and during the occurrence of data processing, the chipset can leave a
given row of a given bank (which has been accessed before) "open". As
an example, if the very next request accesses the same row, the chipset
does not have to wait until the sense amps are charged. This is referred
to as a "page hit". The RAS to CAS latency will be 0 (zero) cycles
and the output buffers will contain the right data after the CAS latency.
In simpler terms, a page hit makes sure we only have to wait until
the right columns are found on the sense amps, which already contain the
There is a down side though,
as the row requested by the chipset might not be the one that is open,
which is referred to as a page miss. In that case the RAS to CAS
latency can be 2 or 3 clock cycles, depending on the quality of the SDRAM.
If the chipset has left open a certain row on a certain bank, and the
data requested is in a different row in the same bank, latency gets worse.
When this occurs, the sense amps have to write back the old row before
they can charge the new one. Writing back the old row takes a predetermined
amount of time referred to as tRP (Precharge
SDRAM modules are usually defined
by three numbers, such as 2-2-2 or 3-2-2. The first number refers to CAS
Latency, the second to tRP (time to switch
between memory banks), and the third to tRCD.
Bear in mind that these numbers mean different things for different bus
speeds. As an example, these are the calculations for 100 Mhz. (1 clock
cycle = 10 nanoseconds):
At 100 MHz.
= 25 nanoseconds
||25 / 10 = 2.5 - rounded to 3
= 20 nanoseconds
||20 / 10 = 2
= 20 nanoseconds
||20 / 10 = 2
If we were to calculate these
figures at 133 Mhz., with 1 clock cycle equal to 7.5 nanoseconds, the
results would be:
At 133 MHz.
= 25 nanoseconds
||25 / 7.5 = 3.33 - rounded to 4
= 20 nanoseconds
||20 / 7.5 = 2.67 - rounded to 3
= 20 nanoseconds
||20 / 7.5 = 2.67 - rounded to 3
This second example, with a
CAS Latency of "4", would be invalid in a 133 Mhz. system, as the PC 133
SDRAM specification does not permit this.
CAS Latencies are usually written
as CAS2 or CAS3, so just how important is this?
In the real world, unless your
system is up on the cutting edge of technology and you're pushing performance
to the limit as do some over-clockers, or gamers, it may have some relevance.
On the other hand, in everyday systems the relevance is nominal at best.
CAS3 means that at 100 Mhz., the amount of time required for the first
memory access in a burst is increased by 10 nanoseconds or less. Divide
this figure by 4 to average the increased time across four bursts, and
you have an improvement of less than 2.5 nanoseconds over CAS2. We need
to underscore the term relevance as it pertains to CAS Latency and changing
memory modules on the average system. If you had a Pentium III 600 to
866MHz. computer, as an example, and you used this for surfing the Internet,
using Microsoft Office or Corel Office, Adobe products etc., and changed
your memory modules from those having CAS3 to CAS2 latencies, you wouldn't
be able to notice any difference. But again, if you are pushing your system
to the limits, this could become critical.
can I disable ACPI and what
are the advantages and disadvantages of enabling ACPI?
First off, I think a little
introduction is needed as to what ACPI is.
ACPI (Advanced Configuration
and Power Interface) is a power management specification that allows the
operating system to control the amount of power distributed to the computer's
devices. Devices not in use can be turned off, reducing unnecessary power
expenditure. ACPI defines a new interface to the system board, and enables
the OnNow design initiative for instantly available PCs.
ACPI is actually a substitute
for APM (Advanced Power Management) at the hardware-software level. Unlike
APM, which deals with the power management directly through the BIOS,
ACPI, instead exposes the tables present in the various installed hardware
devices in the system to the operating system. ACPI, in effect, hands
off control of power management to the operating system. ACPI is merely
a standard implemented by hardware vendors to provide standardized interfaces
that are ACPI compliant. In this manor, much of the work done for power
management is thus performed by the operating system instead of the BIOS.
ACPI was developed by Intel, Toshiba, Phoenix, Compaq and Microsoft to
establish common interfaces for the hardware devices in a system to allow
various operating systems direct control over the power management of
the entire system, devices and operating system alike.
Some advantages are:
1) Moving power management functionality
into the OS makes it available on every machine on which the OS is installed.
The level of functionality varies from machine to machine, but users
and applications will see the same power interface on all ACPI compliant
2) Power management is not restricted to
the BIOS and hardware levels. With ACPI and a suitable model, applications
can tune themselves and conserve power.
3) There is much less state information
for the BIOS to retain and manage because the OS manages it. This leads
to a simpler implementation at the BIOS level.
4) Power management algorithms are unified
in the OS, yielding much better integration between the OS and the hardware.
5) The OS can deal with power management
of devices dynamically, as the interface provides dynamic registering
or loading and unloading of devices.
Some disadvantages are:
1) Problems will arise when an ACPI BIOS
puts an _ADR device into a deeper sleep state than its bus is
expecting. It is important to remember that any buses (including PCI)
do not expect devices to disappear from the bus when they are powered
down. If a subsequent enumeration of that bus takes place, the bus driver
will believe that the powered-down devices have been removed from the
system. In Windows 2000, this may result in an "Unsafe Surprise Removal"
dialog box. For Windows 98, no dialog box will appear; the disappearance
of an IDE device will result in an IDE error bluescreen.
do I clear the password?
PC Protect passwords Text passwords
YODA74 from PCGuide:
If going with Password Protected
PC,turn off the system and search the motherboard for a Clear CMOS Password
jumper. This jumper lets you clear the password without wiping out the
entire contents of CMOS RAM. The jumper can be hard to find. Check the
motherboard's documentation or manufacturer's Web site for information.
Once you find the proper jumper, set it and reboot the system. When you
see a BIOS message that says, "Password cleared," turn off the PC, reset
the jumper, and boot normally.
If there's no jumper, remove
the battery, which wipes the CMOS RAM's contents. Some chips hold a latent
charge longer than others, so it may be a while before you can return
the battery to the PC. (If you put the battery back in too quickly, the
CMOS's memory may not have cleared yet.) After you reset the date, time,
and hard-drive parameters, use the BIOS Default option to restore general
my BIOS flashable?
To determine if your motherboard
uses a CMOS chip that is flashable your going to have to examine the chip
ID on the chip itself. In a lot of instances there is a sticker on the
top of the chip that identifies the manufacturer. You can pull the sticker
back gently to reveal the chip information. Replace the sticker once you
have acquired the chip information. The following list contains chips
that are flashable:
m29F010: AMD 5 volt flash ROM
Am28F010, Am28F010A: AMD 12 volt flash ROM
AT28C010, AT28MC010, AT29C010, AT29LC010, AT29MC010, AT49F002T: Atmel
5 volt flash ROM
CAT28F010V5, CAT28F010V5I: Catalyst 5 volt flash ROM
CAT28F010, CAT28F010I: Catalyst 12 volt flash ROM
28F010: Fujitsu 12 volt flash ROM or ISSI 12 volt flash ROM
HN58C1000: Hitachi 5 volt flash ROM
HN28F101, HN29C010, HN29C010B, HN58C1001, HN58V1001: Hitachi 12 volt flash
A28F010, 28F001BX-B, 28F001BX-T, 28F010: Intel 12 volt flash ROM
M5M28F101FP, M5M28F101P, M5M28F101RV, M5M28F101VP: Mitsubishi 12 volt
MX28F1000: MXIC 12 volt flash ROM
MSM28F101: OKI 12 volt flash ROM
KM29C010: Samsung 5 volt flash ROM
DQ28C010, DYM28C010, DQM28C010A: SEEQ 5 volt flash ROM
DQ47F010, DQ48F010: SEEQ 12 volt flash ROM
M28F010, M28F1001: SGS-Thomson 12 volt flash ROM
28EE011, 29EE010: SST 5 volt flash ROM
PH29EE010: SST ROM Chip - Flashable
TMS29F010: Texas-Instr. 5 volt flash ROM
TMS28F010: Texas-Instr. 12 volt flash ROM
W29EE011, W29C020C, W49F002U: Winbond 5 volt flash ROM
W27F010: Winbond 12 volt flash ROM
X28C010, X28C010I, XM28C010, XM28C010I: XICOR 5 volt flash ROM
29LVxxx - 3V Flash memory (rare)
28Cxxx - EEPROM, similar to Flash memory
27Cxxx - With window. EPROM: read-only, requires programmer to write and
UV to erase
Anything without a window that
doesn't have a 28, 29, or 49( the latest chip models) as the preceding
numbers of the part number is most likely a standard ROM and not flashable.
edwelly from TechIMO asks:
does BIOS stand for?
BIOS stands for Basic Input/Output
System. For a detailed explanation of the BIOS and how it works, please
refer to the beginning of this FAQ for more information: What
is the BIOS and how does it work?
does CMOS stand for?
CMOS stands for Complementary
Metal Oxide Semiconductor. Information saved in the BIOS setup program
is stored here in RAM. The settings are maintained through the CMOS battery
located on the motherboard. Power is trickled to the CMOS IC to ensure
the settings are not lost when the system is powered down or unplugged.
Battery life varies with each type used. In most cases, you can expect
about 3-5 years life span out of most CMOS batteries. In some cases, however,
batteries bought from stores are DOA. Always check the expiration date
on batteries before purchasing them. Here's a classic case of buyer beware.
Once you buy it, it's yours to keep.
For a detailed examination
of what CMOS is, please refer to the following website for information:
Complementary Metal Oxide Semiconductor (CMOS) Structure.
Shadowfax from XiBase asks:
is hot swapping the BIOS? [don't no the proper name for replacing the
BIOS when the computer is already running]
is a means of recovering your bios in the event of a power failure or
a corrupt flash file. The Hot Swapping process involves finding or gaining
access to a computer that has the same type of BIOS ROM chip you have
now. Not necessarily the same manufacturer but the same page bytes as
well as programming voltages and pin out's.
would involve booting the computer that you are going to use to recover
your bad bios and after the boot is complete swap bios chips while the
power is still applied and then flash the bios with the flash file that
is for your broken computer. This procedure is not without risk as you
may ruin the motherboard in the computer you are trying to use to recover
the bad flash bios. Static electricity is the common enemy when it comes
to any electronic component.
a flash in this operation the use of the /F parameter is required. Using
this switch will force the flash to go through(Award Bios Only). Also,
this parameter must be used by itself. No other parameters can be used
in conjunction with it.
be taken if you are considering performing a how swap. SO NOT USE A METAL
TOOL TO EXTRACT THE CMOS CHIP! Use a small strong piece of plastic or
other nonconductive device to perform the extraction. Care should be taken
when you insert the dead BIOS also. Attention should be given to the leads.
These are fragile and conductive. Hold the chip from the ends and not
the sides. You could easily pile on more damage tot he chip from ESD if
you do. Carefully insert the chip. DO NOT FORCE IT! You will most likely
bend one of the leads in doing this. Slowly maneuver the chip into place.
A little force it fine, just be careful to not push to hard.
korgul from TechIMO asks:
do I replace the CMOS battery?
the battery on your motherboard is a straight forward task. With any new
motherboard out there and nearly all motherboards since the Pentium was
introduced, the CR-2032 battery has been used to provide power to the
is pretty much the standard with all motherboards now. To replace the
battery, examine the retaining mechanism for it. It seems that just about
every motherboard uses a different method of retaining it. Once you have
figured out how to remove it, just pop it out and insert the new battery.
older motherboards, the battery was soldered on. This is especially true
with the 386 and early 486 motherboards. The biggest problem with these
batteries was corrosion. A leaky battery would eat the copper on the motherboard
and other components around it. To solve this problem the industry has
moved to the battery implementation using the CR-2032. However, there
is still the issue of how to replace the older batteries. If your adept
at soldering, desoldering the battery and replacing it should be a straight
forward procedure. For those of us who would rather not solder, there
is a way around it. With a lot of the older motherboards, a jumper was
available to attach a battery. This allowed for easy replacement of the
battery on these older motherboards. If this is the case, you can simply
purchase a battery from a local computer store or one of the big name
brand stores like CompUSA, etc.. Something like the following:
for it connects to the jumper on the motherboard for an external battery.
Ensure that you check your motherboard for the type of battery and the
method of replacement, especially for the older motherboards. Using the
incorrect battery may lead to a corrupt BIOS and/or dmage to the physical
Fury from XiBase asks:
do I do if my power went out in the middle of a BIOS flash and my computer
will no longer start?
as of today have a boot block feature for situations such as this. This
feature will allow the computer to boot to the floppy and flash the BIOS
with a new flash file that will over write the data corruption as a result
of the power failure. At certain times the video will not be available
and you will have to create a flash disk that uses a autoexec.bat file
that will automatically flash the BIOS without user intervention upon
boot up. If you still don't have any luck with that you could always try
the Hot Swap procedure or get a replacement BIOS from several different
Kieren from Binary’s BIOS Mods asks:
are the optimal settings for my BIOS?
a question that only you can decide on actually. Every system is used
for a different purpose, graphics workstations, home based server, development
workstation, all of the above, or just e-mail/Internet system. Each feature
has it's own purpose and each has it's advantages and disadvantages. For
the best reference, I could copy the entire document from Adrian Wong's
site, but then I would be wasting bandwidth. See for yourself. The
Definitive BIOS Optimization Guide, an absolute must for any BIOS
tweaker/hacker. Also, be sure to check out the bottom of the page. There
you download the entire document in various formats.
can I find information on how to modify the boot logo?
always post a message here at Bios
Central Forums in the Advanced
BIOS Mods area pertaining to what logo you want and the possibility
of doing the mod. You will need a a utility that is meant for the BIOS
type and version that you are working with. For example you would use
Cbrom for the Award BIOS's and AMIbcp75 for the AMI BIOS's. There also
is a utility named Awdhack that will do the Medallion BIOS's and some
of the ones that Cbrom won't do. There are a few little requirements that
need to be met before this can all take place. If you are changing the
EPA logo there are different versions of the logos. If you are going to
do a full screen then yet again there are different needs to be met. This
modification is not hard and if anyone has a desire to change the picture
they see when their computer boots up then this is for you.
IS FOR AWARD BIOS'S ONLY" You will need three files to change the boot
or epa logo and flash it.
Cbrom "Either version 2.07 or 2.15
"The newer the better"
you want to use your existing bios you will have to make a copy of it
for the modification. Using a boot disk with Awdflash on it just type
Awdflash /SY and that will make a backup copy of it. Just name the backup
file backup.bin. If you want to use a newer bios flash file there is no
reason to do this step.
you are going to change the logo(s) in a newer bios flash file just download
the version that you want and extract it to a folder in your system. Also
copy cbrom to this folder as well as the logo (s) that you will be changing
to. If you are going to use a backup of the bios flash just copy it from
the floppy to the same folder where cbrom and the logo(s) are located.
for Awdflash and Cbrom is the following commands Awdflash /? or Cbrom???
the DOS prompt window In Win9x and navigate to the folder where the files
are located.(Windows NT, 2000, XP have issues with DOS programs and it
is best not to run them within the OS. If you have one of these OS systems
download the BiosMod Utility V1 in the utility download section.)
sure that all files needed are in the same folder.
assume you already have a favorite .BMP or .EPA of a penguin or daemon
handy. (640x464, 16 colors, Windows BMP or the proper EPA version)
kicks, examine your old BIOS ROM: CBROM??? mybios.bin /D See the various
components there? The one we're after is the logo bitmap, by default "welcome.bmp"
your bios file: CBROM??? mybios.bin /logo penguin.bmp for the full screen
boot logo or CBROM??? mybios.bin /epa myepa.epa for the epa logo. This
overwrites mybios.bin, creating the file for your new BIOS. If your logo
is too complicated and doesn't compress well, you may run out of space.
You can use CBROM to tell you whether or not your BIOS image with the
new logo is "full" or not.
all went well and you saw the program add the logo(s) It will show a percent
value you have succesfully added a new logo or epa. Now copy the modified
bios file to the floppy.
is the time to reflash the chip and see if you did it correctly. Boot
the computer using a boot disk with no config.sys or autoexec.bat and
the Awdflash program on the disk as well as the modified bios file. Just
type in Awdflash and the flashing process will begin. Answer yes when
it asks if you want to make a backup of the current bios.
a BIOS upgrade
The PC does not boot after
upgrading the BIOS:
If you have removed the CMOS
chip for flashing, double check that you have inserted the CMOS properly.
Ensure that the orientation of the IC is proper and that all pins are
properly inserted. If you have flashed the BIOS with the wrong BIOS update,
then the only recourse is to replace the CMOS IC outright.
You accidentally reset or
power down the system during the BIOS flash. Now the system won't boot:
Basically what has happened
here is the BIOS was only partially programmed. In this case, the BIOS
is corrupt. If possible, you can remove the IC and reprogram it in a EEPROM
programmer. Another option is performing a "hot swap" of the
chip with another motherboard with the same chip. Otherwise, a replacement
of the CMOS IC is required. There is no chance in fixing the IC in it's
The BIOS upgrade proceeded
properly, but now the system performs sluggishly, erratic or error appear
that never occurred before:
Several things can attribute
to this. It could be caused by a bad flash. In this case, reflash the
BIOS with the backup of the BIOS made during the flash (you did make that
backup...right?). After restoring the backup, you can reflash the BIOS
again with the new update. Other possibilities include new settings within
the BIOS. Memory timings area big issue. Enter the BIOS setup program
and restore BIOS defaults or Fail Safe Defaults. Then, once your system
is stable, tweak the memory timings to you desire. Other issues can be
incorrect port settings, features that were enabled when the flash took
effect and features that were disabled. Check the following: "System
Bootup Speed", "Speculative Lead Off", "Turn Around
Insertion", "ISA Speed - ISA Clock to:", "16 Bit Recovery
Time", "Pipeline Cache Timing", and other speed settings
that may effect performance.
You just upgraded the BIOS
and now cannot boot from the floppy drive:
Enter the BIOS setup program
and check the Boot Sequence. Ensure that the sequence is set to A:/C:.
Ensure that the floppy drive is setup properly in the BIOS as well and
that the system is not looking for a B: drive too.
You get a message saying:
"Incompatible BIOS translation detected - unable to load disk overlay":
A lot of people upgrade their
BIOS to get support for larger hard drives. In some cases, users have
installed a software overlay that allows the operating system to properly
see the entire hard drive. What happens with the BIOS in this case is
the LBA (Logical Block Address) is now enabled. What you will need to
do is enter the BIOS setup program and disable LBA mode for the hard drive
in question. If more than one drive is configured for a software disk
overlay, then you'll need to configure all drives properly by disabling
LBA on them. With some disk utilities, the user can remove the software
overlay safety. Beware. This is no guarantee that the system and the hard
drive will work properly. Always backup your data before removing a disk
overlay. You may not be able to get it back.
Your system boots with an
error message saying "BIOS Boot Block Loaded":
What most likely has happened
here is the BIOS is not being read correctly by the system. This is usually
due to a BIOS not being cleared properly. Power down and clear the BIOS.
Ensure that you pull the system power cord when clearing the BIOS to ensure
proper erasure. Resetting the BIOS, in most cases, will clear this up.
If the problem persists, then insert a bootable floppy and reflash the
BIOS with the backup you created during the flashing. Once your BIOS has
been restored, you can proceed with flashing the BIOS again. After flashing
the BIOS, always clear it before proceeding.
You may also receive this message
if the BIOS flash did not complete, you flashed the BIOS with an incompatible
BIOS update, or some other anomaly occurred. In any case, you should be
able to recover the BIOS as long as you can boot to a floppy. Remember
to boot from a floppy that doesn't have any drivers being loaded. Once
you have booted the system you should be able to either restore the BIOS
from the backup you created or reflash the BIOS with the BIOS update.
You get an "Insufficient
memory" error when running the flashing program:
This means that the flashing
utility has run out of memory to perform the flash. Enter the BIOS and
disable the video and system caching as well as all types of Shadow Memory.
Make sure the boot floppy you are using is not loading ANY device drivers,
such as CD-ROM or mouse drivers.
P. McNichols, BIOS Update
Guidelines, 1990 Dynamic Learning Systems.
S. Bigelow, Troubleshooting,
Maintaining & Repairing PCs 2nd Ed., 1996 McGraw-Hill.
A. Wong, The BIOS Optimization
Guide Rev. 6.2, 1998-2001.