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GPO?
Posted: Fri Mar 14, 2003 5:00 pm
by sulbert
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
Posted: Fri Mar 14, 2003 9:03 pm
by Rainbow
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.
Posted: Fri Mar 14, 2003 9:46 pm
by sulbert
Thank you, Rainbow
So special flash utility (which is able to put these GPO pins to the right state) is needed for those boards?
Posted: Fri Mar 14, 2003 10:35 pm
by Rainbow
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
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.
