This repository contains patches for Adaptec SCSI BIOSes and ASPI drivers (currently for the 2740 and 2840) to support the Phoenix/Microsoft Int13 extensions used to access hard disks above 8GB in LBA mode. To avoid potential copyright problems, this repository does not contain the actual Adaptec code. Instead, this repository contains an assembler source code file that generates an object file that contains only the locations that need to be overwritten to add Int 13 extension support to the respective files.
To apply the patch, you need the assembled form of the patch, which can be generated using MASM or a compatible assembler like Borland's TASM or JWASM. This patch has been tested to assemble correctly on both TASM and JWASM, even though TASM produces a different output because TASM defaults to single-pass mode and the patch contains a non-annotated short forward jump. Both assembled versions are functionally identical. You can also just download the latest GitHub release which includes an assembled object file.
To apply an object file as patch, my tool omfpatch can be used. Release 1.1 is known to work with this patch. You can choose to download either the DOS or the Win32 version of omfpatch depending on the system you want to use to apply the patch.
Patches for following SCSI BIOSes is included
| Controller | Version | patch object | map file | ROM chip size |
|---|---|---|---|---|
| AHA-152xB | 1.15 | 152xB115.obj | bios16K.map | 64KB (512kBit) |
| AHA-274x | 2.11 | 274x-211.obj | bios16k.map | 32KB (256kBit) |
| AHA-284xVL | 1.01 | 284x-101.obj | bios1632.map | 64KB (512kBit) |
| AHA-284xA | 2.0 | 284x-20.obj | bios1632.map | 64KB (512kBit) |
Furthermore, a patch for the following ASPI driver is included
| Driver | Version | patch object | map file | file size |
|---|---|---|---|---|
| ASPI2DOS.SYS | 3.86S | none | none | 35330 bytes |
| ASPI7DOS.SYS | 1.42 | a7-142.obj | a7-142.map | 36160 bytes |
There is no need patch ASPI2DOS.SYS, at least concerning verion 3.68S in conjuction with the AHA-152xB with ROM 1.15. The EDD functionally in the ROM stays active, even if the ASPI manager is loaded with the message Int 13H routed through ASPI manager.
Note that the latest 274x BIOS (2.11) seems to not be available for download from the Adaptec / MicroSemi. Their page has version 2.10. This patch does not apply to version 2.10. You can obtain the ROM image by reading it from an controller that has the latest version. The ROM chip is an OTP chip labelled 549306-00 D BIOS 7D00 (c) 1993.
The same applies to 284xA: while BIOS version 1.01 is available on the Adaptec site, it seems to work only with 2842VL controllers. The revised 2842A controller shipped with BIOS 2.0, which is not available on the Adaptec site, and fails to work with the 1.01 BIOS. I also expect the 2842VL to fail with the 2.0 BIOS.
Again, the version 1.15 for the 152xB is not available from Adaptec / MicroSemi. You can obtain the ROM image by reading it from an controller that has the this version (which is supposed to be the latest). The ROM chip is an OTP chip labelled 931604-00 A BIOS 1A74 (c) 1996. Please understand that the 152xB and the 152x without "B" are different controllers. The 152xB uses the latest Adaptec ISA chip, the AIC-6370. The AIC-6370 is backwards compatible with software written for the 6260 and 6360, even if the software programs the controller on the register level. However, the AHA-152xB BIOS accesses the advanced features of the AIC-6370, like more embedded BIOS parameter RAM, and the facility to update the ISAPNP configuration settings. The 152xB BIOS will fail on earlier 152x-series controllers.
You can run omfpatch 152xB115.bin bios16k.map 152xB115.obj to create a patched BIOS image for the 1520B/1522B.
You can run omfpatch 274x-211.bin bios16k.map 274x-211.obj to create a patched BIOS image for the 2740.
You can run omfpatch 284x-101.bin bios1632.map 284x-101.obj to create a patched BIOS image for the 2840VL.
You can run omfpatch 284x-20.bin bios1632.map 284x-20.obj to create a patched BIOS image for the 2840A.
For the AIC-7770 based controllers, the patched BIOS identifies itself as "EDD 1.0" instead of just "Release" to indicate the extended disk drive specification. For the AHA-152xB, the patched BIOS identifies itself as "1.15E" instead of plain "1.15".
If your BIOS version doesn't match any of the provided patches you can try creating your own patch by finding the corresponding offsets in your BIOS image. That's an example how 284x 2.00 patch was created:
- Create copy of asm file for similar controller model (for example 284x-201.asm).
- Get the data located within offset variable in known BIOS version, 4 bytes is enough.
ResetLocalStateOfs = 0C80h- in version 1.01 of the BIOS you can find such values:06 51 8A 46 - Find the offset of these 4 bytes in your BIOS version - they should be not far from the original offset.
In BIOS v2.0 these files are located within offset
0CA8h- 28h or 40dec bytes later. - Replace the offset in your asm file with the value you just found.
- Repeat steps 2-4 for every variable, usually if you find the first offset "delta" every other will be the same or similar.
To compile your new patch file use the command jwasm -Zm 284x-201.asm.
If you patch your BIOS and something goes wrong, the computer may become unbootable. It is recommended that you have a way to recover your BIOS, like an external flasher connected to a different computer. Make a backup of your BIOS before you install a patched BIOS.