HDD Patching

Ritchie · BIOS Guru Joined: 30 Oct 2002 Posts: 761

Just out of curiousity, why does a BIOS need to be patched for HDD support to 32GB before it can be patched to 64MB or 128GB?

Apparently an old BIOS can be manufacture patched beyond 8GB, and then Wim's can patch it further if required.

I am wondering what the differences are between the way that Wim's patches BIOSs and manufactures patch BIOSs that mean that Wim's cannot patch an 8GB limitation while the manufacturer may be able to. Evidently there must be different tools used and I am curious as to the technical differences between the way these tools work.

Also, I have noted in a few topics that Wim's patches are stated to sometimes be difficult to detect drives once the patch is applied, although in most cases this does not appear to be a problem. I am curious about this also.

Denniss · Posted: Sat Jun 05, 2004 11:32 am Post subject:

With the 8GB problem it needed to rewrite the INT13h extension as is needed for the 128GB problem .
The 32/64GB things are only small bugs/problems which require much less work .
AFAIK the 32GB thing are only some bytes to be set different
_________________
32GB/64GB-BUG patched and tested BIOS
Uniflash - flash anything everywhere

Ritchie · BIOS Guru Joined: 30 Oct 2002 Posts: 761

Thanks - In other words you cannot extend the 13H. So if there are new minor bugs once a manufacturer has rewritten the 13H extension then Wim's may also be able to correct these.

I do wonder if the manufactures bug the BIOSs on purpose hoping that people will purchase new boards rather than seek BIOS upgrades.

Afterthought: Out of interest, could you extract a rewritten 13H extension out of one BIOS and use this to overwrite the appropriate area of a BIOS image that requires this? I suppose you would have to know what part of the file to overwrite, and it could be different in different BIOS images.

Denniss · Posted: Sun Jun 06, 2004 11:52 am Post subject:

Might be possible but this is reverse-Engineering/hacking a copyright-protected software and should be illegal
_________________
32GB/64GB-BUG patched and tested BIOS
Uniflash - flash anything everywhere

KachiWachi · Posted: Sun Jun 06, 2004 1:14 pm Post subject:

For something like this, the larger sized HD were not readily available (read - too expensive) to the public, so a "minor bug" could be left in, and is acceptable in the industry.

Once the hardware catches up and starts to exercise the buggy routine however, that's where the problems begin.

Of course, a manufacturer is always developing new products (otherwise we'd still all be running 2x86's!!) so support for older models naturally falls to the side, or to the aftermarket.

As for copying firmware, technically that infringes on the copyright, but you could always write your own code "based" on a known working model...
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CPU - DFI 586IPVG, K6-2/+ 450 (Cyrix MII 433), i430VX, 128MB EDO.
BIOS patched by BiosMan (Jan Steunebrink).

Ritchie · BIOS Guru Joined: 30 Oct 2002 Posts: 761

In other words, Wim's BIOS is:

1) Providing BIOS patches to support relatively modern HDDs in machines that originally and technically supported them.
2) Providing BIOS patches that are easy to patch for relatively modern HDDs.
3) Providing BIOS patches that can be created and made available legally.

That all sounds quite good, and quite fair. It is good to know patches of this nature are available when I come across machines that require them.