Quote Originally Posted by Brama View Post
I extracted from BIOSes every single module decompressed and the differences shown by WinHex are only the build number and date.

Boot block (module 08) is the same bit per bit.
Module 1B has only the usual date and build differences and some bytes at the end that I think doesn't matter.........

Extended Boot Block (module 15 with EBB), see below




This is HOLE1 compare, very similar to EBB, probably where EBB fits:

The changed bits in 1B probably do mean something. You'd need to throw both a previous 1B and current 1B into IDA and disassemble the changed bits to see if they are actually different. A few changed bytes account for a few instructions difference usually. if I recall you need to disassemble the 1B module as 32-bit code. I'll try find some time to disassemble both and see the diffs this week.