The aic7xxx driver defaults to EXTEND_TRANS_[AB] being enabled if a seeprom is not found. This causes a disk partitioning scheme made with the v5.0.19 driver (shipped with RedHat 5.1) to be invalid after an upgrade. This can no be fixed using command-line args to the driver or any BIOS settings. I got around it by making it default like the driver I originally installed with. I can't see why there is a valid reason to force Linux to use Translation when it doesn't need it. Anyways, basically Redhat is screwed now since they shipped a product that defaults the other way... there is no way to make everyone happy. Someone should add a "noextend" parameter for the driver.
I can confirm. It was introduced in 2.0.36pre14. The driver should really be made to read the BIOS setting again. I have reported it on 11 Nov 1998 on linux-kernel@vger..., as well as to Alan and Doug.
Doug, do you have anything to say about this one?
Easy way of getting system to boot again: Having disk partitioned without extended translation, LILO install in 2.0.36 kernel results in unbootable system. But after enabling extended translation in BIOS the system boots (fdisk is still confused though).
Patch available ftp.redhat.com/pub/aic/5.1.5/aic7xxx-5.1.5-2.0.36.patch.gz. Fixes this problem.