[flashrom] Flashrom failing to find EEPROM chip it could previously see

[Teetshorn, Matthew A.]

Hello,

I have a question regarding a recent issue with flashrom not identifying an EEPROM chip that it formerly was able to program.

We have been doing some BIOS testing at my organization by installing a custom AMI BIOS on a W25Q128FV BIOS chipset.  Most recently I recovered the BIOS using flashrom and the BusPirate programmer in order to flash a known good BIOS which was successful.  I then booted and used the AFUDOS tool to flash a custom ROM image.  I did this by invoking the '/P' AFUDOS option to "theoretically" only program the custom BIOS image into the main BIOS image region, leaving the FDT, ME and reserved regions intact.  Despite selecting only the BIOS region during this process, the AFUDOS tool listed many onscreen steps involving erasing/verifying many regions (including ME, FDT, NVRAM, etc.) but seemed to exit out cleanly after flashing.  Now the board will not boot and the flashrom/BusPirate combo is failing to discover the W25Q128FV chip when I attempt to recover to the known good ROM.

My primary question is then, is there anything that may have been done, either in general or specific to the AFUDOS /P command, that may have done something to the EEPROM that would cause flashrom to fail to identify it?  I am not an expert in EEPROM chip technology and am not quite sure whether the last reprogram could have done something or if the problem is something else that just coincided with the last flash.  What types of problems could cause flashrom to fail to identify an EEPROM that it was previously able to find?  We have already verified the electrical contacts on our SOIC clip and since we were able to identify/program immediately prior to this we can assume we do not suffer from in circuit capacitance issues on VCC.

Thanks in advance,

Matthew Teetshorn | Draper
Member Technical Staff, Mixed Signal Embedded Systems: GBC6
555 Technology Square | Cambridge, MA 02139
Ph: 617.258.3592 | mteetshorn at draper.com<mailto:mteetshorn at draper.com>

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