BIOS Questions that don't belong in the other forums. Read them!
#57047 by fdm
Mon Oct 17, 2011 11:26 pm
I have an old Gateway with an Intel EA81510A motherboard and would like to replace the dumbed-down OEM bios with retail Intel bios. I am aware I can use the recovery procedure to accomplish this, but unfortunately I have been unable to locate any floppy disks to use. Intel uses signed bios, so instead of targeting the bios I have taken to reversing the dos flasher. From what I have gathered online, it is supposed to verify the bios via the 3 digit vendor code(15A for Gateway, 86A for Intel). With this, I used softice to locate how/where the vendor string is loaded in memory and how the program accesses it later. To pass the vendor check, I shortened a random string and used the freed space to add the version and id from the retail Intel bios. Then I changed the segment and address that the program uses to access the detected id string to point to my new inlined one. I tested this patch with Gateway bios and 15A set as the vender string, and it was able to successfully flash. Then I tried to flash unmodified retail Intel bios with 86A as the vender code and it returned Authentication failure, the same error I get if I try to modify the bio's headers. Since I am unsure what to make of this, I thought maybe someone here might have some insight on what other information it might be gathering from my board to determine that might make it fail validation.