AMI BIOS on Am386SX-40 == no option ROMs?

[coredump4]

Hi,
I borrowed a generic Am386sx-40 PC from a friend for some ISA NIC boot ROM testing. However, the machine doesn't seem to recognize any card's option ROM, even cards I'm certain work. I gave up on the NICs and even tried my trusty Adaptec 1522A to no avail.

The CMOS setup has options to shadow the system and VGA BIOSes, but that's the only mention of any ROMs. It's a AMI BIOS from '92 (eg, no PnP).

What am I missing? Is it possible this simple BIOS doesn't scan for option ROMs or have I suffered enough brain bit-rot that I'm missing something obvious?

thanks!

 

[ph4nt0m]

Older BIOSes have no means for ISA ROM integration. They are not even compressed.

 

[coredump4]

Embedding the option ROM in the BIOS would be a pipe dream... I'd just like it to recognize those on ISA cards. You ever heard of a BIOS that doesn't scan for these?
I need to look through my stock and see if I have an ISA BIOS POST card... I know I've got PCI.

 

[mbbrutman]

Any 386 class PC system should scan and recognize option ROMs. VGA was implemented as an option ROM, as are SCSI cards. I think the only machines that do not scan for option ROMs are the first generation IBM PC 5150s with the first BIOS version. (Please, nobody bring up embedded machines - those are corner cases.)

I have an AMD 386-40 with AMI BIOS. Turn off the ROM shadowing. Turn off the ability to cache those regions of RAM. And turn off any virus protection options, just in case. You can also try setting the bus speed slower; 8Mhz might be too fast for the card.


Mike

 

[Ruud]

Just another idea: don't change things for the moment, insert your card, boot the machine and use DEBUG to have a look at the address where the ROM should reside. You should see "55 AA" as the first two bytes. If you don't, for one or another reason the ROM cannot be seen or, just a guess, it is replaced by shadow-RAM but the ROM has not been copied.
After doing what Mike asked and the ROM still doesn't start up, have another go with DEBUG. If you still don't see the two bytes, then there is something wrong with the hardware of the mobo IMHO.

But if you do see the two bytes, you could try to start the ROM by hand by executing "g=xx00:3" where xx is the page where your ROM is found. That could be C8, CA, CC, D0, D8, etc., etc. If you still have no result, I'm out of ideas for the moment.

 

[ajacocks]

Just another idea: don't change things for the moment, insert your card, boot the machine and use DEBUG to have a look at the address where the ROM should reside. You should see "55 AA" as the first two bytes. If you don't, for one or another reason the ROM cannot be seen or, just a guess, it is replaced by shadow-RAM but the ROM has not been copied.
After doing what Mike asked and the ROM still doesn't start up, have another go with DEBUG. If you still don't see the two bytes, then there is something wrong with the hardware of the mobo IMHO.

But if you do see the two bytes, you could try to start the ROM by hand by executing "g=xx00:3" where xx is the page where your ROM is found. That could be C8, CA, CC, D0, D8, etc., etc. If you still have no result, I'm out of ideas for the moment.

Excellent suggestions, Ruud. We’ll definitely give it a shot.

- Alex

 

[coredump4]

Just another idea: don't change things for the moment, insert your card, boot the machine and use DEBUG to have a look at the address where the ROM should reside. You should see "55 AA" as the first two bytes. If you don't, for one or another reason the ROM cannot be seen or, just a guess, it is replaced by shadow-RAM but the ROM has not been copied.
After doing what Mike asked and the ROM still doesn't start up, have another go with DEBUG. If you still don't see the two bytes, then there is something wrong with the hardware of the mobo IMHO.

But if you do see the two bytes, you could try to start the ROM by hand by executing "g=xx00:3" where xx is the page where your ROM is found. That could be C8, CA, CC, D0, D8, etc., etc. If you still have no result, I'm out of ideas for the moment.

Thank you!
I did not know that debug trick... very useful!

 

[coredump4]

Made some progress. There's some kind of peculiarity with this system, but it will recognize option ROMs on select ISA cards.

Tested:
Adaptec 1522A, stock ROM => no;
D-Link DE-200 w/ XTIDE 2.0.0b3 ROM (works in at least 1 other system) => no;
Farallon NetLINE NIC (Realtek RTL8019AS) => YES

There wasn't any tuning to do, as the BIOS' only ROM-related settings are shadowing of the VGA and system BIOSes, both of which are disabled. There are no bus speed settings, etc.
This at least gets me back on track with my original project, which was to create & test some iPXE ROM images.

Thanks for the help!

 

[Ruud]

Adaptec 1522A, stock ROM => no;
D-Link DE-200 w/ XTIDE 2.0.0b3 ROM (works in at least 1 other system) => no;
Farallon NetLINE NIC (Realtek RTL8019AS) => YES

That makes me wonder what causes a card to work in another system but not this one? One could say "incompatible BIOS" but that is to general IMHO.