Doubt about bios sizes

Hot-swapping and Boot-Block flash & Boot block flash and floppy support
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Posts: 13
Joined: Fri May 23, 2003 7:43 am

Hi there,

I'm new to bios flashing using epprom programmers and now I have a doubt....

The chip I'm interested in is a Winbond W29C011 which is a 1 Mb bios.
1Mb means 128 Kb so I guess no there is no 'boot block' and the whole space is dedicated to 'system block' (following David Oakley name convention).

I download the bios file which corresponds to the mobo I'm trying to resurrect but.... it sizes 256 Kb...!

What's wrong?

Maybe the file used by AWDFLASH (or similiar utilities) from floppy is not EXACTLY the same that should be injected via eeprom programmer????

Hint will be REALLY appreciated.

The UniFlasher
Posts: 3122
Joined: Wed Mar 20, 2002 4:16 pm
Location: Slovakia

128KB BIOSes have bootblock too.
Looks like you have wrong BIOS - either it's not for that board or it's not for that board version.
The BIOS image file is binary image of the data that should be in the chip.
Patched and tested BIOSes are at
UniFlash - Flash anything anywhere
New visitors - please read the rules.
Posts: 13
Joined: Fri May 23, 2003 7:43 am

Thank you very much for replying to my questions.

I'm sure you are right but it is still too strange.

The mobo is well documented at Taiwan Tekran site: ... t=P6Pro-Au

Note that there is no comments about revisions implying changes of bios chip. Bios update file is offered for P6Pro-AU mobos (like mine) and that is strange because flashing using this update (sized 256kb) had ruined my mobo when iit was still working....
If a bios size mobo revision had been made I would expect a notice to prevent users to perform wrong updates....

Anyway, I wonder if it would made sense to flash the available 256Kb file
onto a Winbond 29C020, practically the same but having 2Mb....

Thanks again,

P.D.: I thought 1Mb Bios have not 'boot block' as is stated on paper by S. Oakley:
Posts: 3153
Joined: Thu Mar 21, 2002 8:16 pm
Location: Near Hannover (CEBIT) Germany

Websites often states specs of retail boards and all the files are for them only - maybe yours is/was an OEM-version using a reduced size Bios
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