View Full Version : Replacing the BIOS on a Proprietary System?

February 24th, 2017, 09:05 AM
I have several systems from the 386/486 era, most of which are either HP or Compaq and running on a proprietary BIOS. What I'm wondering is if theres a way to swap out the BIOS on these systems to something less locked down, or are they just stuck needing a setup disk and being as limited as they are?

February 27th, 2017, 10:42 PM
Im gonna take a weekends worth of silence as a no, which is what I thought.

February 27th, 2017, 11:32 PM
Whilst you can't replace the BIOS it might be possible to patch it to remove some of the restrictions...

February 27th, 2017, 11:41 PM
Since HP and Compaq machines of that era were usually highly proprietary hardware wise (they often rolled their own chipsets), the chance of getting a generic BIOS with more options is pretty remote.

The most you could hope for is if you can dump the BIOS and see if there are any hidden options/menus which can be enabled and then reflash the modified BIOS back on to the machine. This is a risky process and can more than likely lead to a bricked motherboard unless you have an external flash programmer you can recover with.

February 28th, 2017, 07:56 PM
What does the stock bios not do that you want to accomplish?

February 28th, 2017, 08:05 PM
What does the stock bios not do that you want to accomplish?

The list of hard drives it recognizes is very short (47 in total, all MFM) and there is no manual setting option, but I can work around that. Mostly I was just curious if it could be done.

February 28th, 2017, 10:06 PM
It should be possible to edit the drive table in the BIOS. I did that in my Toshiba T1200XE and T1600 to add 528mb drives.

Another, easier solution is to put a drive translation BIOS like Promise DriveMax (http://www.vcfed.org/forum/showthread.php?48689-Help-ID-a-486-SBC-Clone-MB&p=378352#post378352) on a NIC with a boot rom socket. It will auto detect the drive type and correct the main BIOS settings.

March 1st, 2017, 09:13 AM
I'll add that some HP BIOS implementations can be annoying at the best. For example, there are several HP systems that require that the PSU have the extra control lead for the fan. If you use a third-party PSU, the board won't boot--just give you an annoying message. I've got a P3 system where the BIOS complains about not having firmware to support a Tualatin CPU--it'll boot, but you'll always get the message and have to acknowledge it with the keyboard.

March 1st, 2017, 09:27 AM
Probably the most annoying thing is the need for a setup disk to access the BIOS. The HDD limitations I can get around well enough (right now Im just using a disk manager), but the fact that I have to boot from a special floppy just to access the BIOS is annoying.