First two bytes need to be "33 C0" (alternative encoding of "mov eax, eax") for some brain-dead BIOSes #32

Googulator · 2024-09-16T21:48:31Z

Some rather brain dead BIOSes use "33 C0" at the beginning of the MBR as a magic number for a "modern" MBR. This is a relic of how all Windows NT-family MBRs begin with "33 C0", while no DOS or Windows 9x MBRs do.

Without this magic value, the affected BIOSes will enable DOS/Win9x-specific workarounds, mostly in relation to drive access, which tend to break large disk access or LBA in newer MBRs.

peterferrie · 2024-09-16T22:22:56Z

I think that this does not affect us, since we are limited to only a single sector anyway, and no further disk access.

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First two bytes need to be "33 C0" (alternative encoding of "mov eax, eax") for some brain-dead BIOSes #32

First two bytes need to be "33 C0" (alternative encoding of "mov eax, eax") for some brain-dead BIOSes #32

First two bytes need to be "33 C0" (alternative encoding of "mov eax, eax") for some brain-dead BIOSes #32

First two bytes need to be "33 C0" (alternative encoding of "mov eax, eax") for some brain-dead BIOSes #32

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