GPO?

BIOS Questions that don't belong in the other forums. Read them!
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sulbert
Master Flasher
Posts: 204
Joined: Wed Jul 17, 2002 1:38 pm
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From uniflash.txt:
fixed flashing on PC Chips M715 board (i440LX) with Award BootBlock BIOS (GPO used for write protection)
found a way to unprotect Flash ROM on Abit BX133-RAID (GPO used), might work on other Abit i440BX based boards too
My (stupid) question is:

What does GPO mean?

Thank you for your answer,
s
Rainbow
The UniFlasher
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GPO = General Purpose Output. Output pins on the chipset which have no predefined function. Board designer can use them to control anything. One of the bad ideas is to use them for additional Flash ROM write protection - such as ANDing one of these outputs with #WE signal to the Flash ROM.
For example - on Abit BX133-RAID (and some other Abit boards too), the BootBlock BIOS can NOT disable this protection so Awdflash is unable to flash the BIOS if it has been corrupted and only BootBlock BIOS works.
Patched and tested BIOSes are at http://wims.rainbow-software.org
UniFlash - Flash anything anywhere
sulbert
Master Flasher
Posts: 204
Joined: Wed Jul 17, 2002 1:38 pm
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Thank you, Rainbow :)

So special flash utility (which is able to put these GPO pins to the right state) is needed for those boards?
Last edited by sulbert on Sat Mar 15, 2003 3:45 pm, edited 1 time in total.
Rainbow
The UniFlasher
Posts: 3122
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When the BIOS is fully functional, Awdflash (for Award) and AMIflash (for AMI) works correctly because they call some BIOS routine which does the unprotect. When the BIOS is not OK, UniFlash is needed :lol: Actually, it's not very intelligent - it checks if the Power Management controller of Intel PIIX4 south bridge has a base address configured. If not, it forces the base address to $6100 (this is unsafe because this might cause conflict with another device) and then changes the state of two GPO pins - one for the M715 and another one for BX133-RAID board. Strange things might happen if these GPOs are used for other purposes on another board.
Patched and tested BIOSes are at http://wims.rainbow-software.org
UniFlash - Flash anything anywhere
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