Can you peel off the sticker and read a part number for the BIOS chip? If it's a 27C010 then it will accept a 128KB ROM.
If its a 27C512 then it is only 64KB and you will need to replace the ROM chip.

If you have an AT29C010 handy that should work fine, just program it with the correct BIOS and plug it in.

I have done this on my own 486 and it worked fine, just make sure you don't plug the chip in backwards.

That one will definitely be a 64KByte chip, 128/256/512KByte chips have 32 pins rather than 28. There shouldn't be any issues dropping a 27C010 with the right BIOS in the socket, though if you're gonna use a flash chip then there might be need to do something about the !WE pin (pin 31 which needs to be at 5V for normal operation).

Thanks for the answers.

Yes I programed a AT29C010, and I will test in the motherboard.

The BIOS file, I download from official ftp site, but I have my doubts / reservations

muon wrote on 2019-01-14, 10:04:

Yes I programed a AT29C010, and I will test in the motherboard.

Did this work out?

Hi guys! A bit late probably, but I'll answers instead. It works, I tested 128k and 64k ROMs in 29C010 and 27C512 ICs, both do work. However, I have here 3.03 Version and it seem to work better, than the newer ones. The newer version seem to have problems detecting the CPU sometimes...

An update, I looked into the BIOS image and the 128k one contains actually two ROMs 64k BIOS for Cirrus Logic VGA followed by 64k BIOS for the mainboard. The mainboard BIOS contains also a block for I/O configuration. Since this ROM image claimed to be compatible with many FIC 486 mainboards, like 486 GAC-V, which actually do have onboard Cirrus Logic and a I/O controller (IDE, Floppy, Serial etc.) this totally makes sense. I cut the BIOS in two and flashed only the mainboard related part on one 64k IC. That worked also without a problem. However, the available I/O setting in the BIOS make it kind of weird, since all this things are to be set by jumpers on the separated controller card.

OK, that worked very nicely for me too. I grabbed the second 1/2 of the rom starting at 0x10000 from the files here:

http://cwcyrix.duckdns.org/ftp-archives/ftp.f … 486/486-vip-io/

Put in on a W27C512, and learned that the non-divot end of the DIP28 chip needs to be flush with the end of the DIP32 socket, and it all worked out.

Thanks a lot, I would not have worked that out on my own. This was great because I only had a spare 64KB eeprom, no 128KB.

So in this case, I downsized the bios from 128KB to 64KB.

Recently I played around with the FIC 486-GVT-2 mainboard and once I upgraded the BIOS from version 3.07G to the newest (beta) BIOS 3.276GN1 (which includes the Y2k fix), the system had trouble POSTing and booting. This beta BIOS should (according to a note on the FIC FTP site which was posted above) be usable on the 486-GVT-2, but turns out it has some problems.

I had a 486 DX2-80 CPU installed and while that ran fine with the older BIOS. However, I could not get it to boot correctly at all with the newer BIOS. Also using the IDE auto-detect tool in the BIOS seems to mess up CMOS settings completely. There are also new BIOS options refering to onboard IDE-, FDC- and I/O controllers, which are not even present on this board, so that's not very trust inspiring either. Also the beta BIOS comes with a Cirrus Logic VBIOS prefixed to the main AWARD image and the GVT-2 doesn't have onboard graphics. It will boot with that, but it's not optimal if you ask me.

After chatting with computerguy096 from The Retro Web which has the same board model and ran into similar glitches with the CMOS settings, he advised me to try setting jumpers for DX2-66 and finally the board could boot into DOS! But once I set jumpers back to 80 Mhz, it got stuck on POST or boot again. He also mentioned that he couldn't get the board to boot with a Pentium Overdrive using the beta BIOS.

My conclusion: The BIOS might work on other FIC boards but on 486-GVT-2 it's definitely very flaky and I can't recommend using it, even with a DX2-66. FIC probably put out this BIOS hastily and didn't really test it thoroughly on all boards it's meant to be for.

ChrisR3tro

Hi,

I am also having an FIC 486-GVT-2 motherboard, but with the older bios from -93 (version 3.03G) , and was thinking about updating it. Having second thoughts now though, when reading your posts..
I do have an DX2-66 though, which seems to be the most compatible. Would you recommend against updating to 3.276GN1?

What are the benefits of updating from 3.03G to 3.07G?

Updating to 3.07G should be fine and I think it's always a good thing to update to the latest stable version.

Concerning the beta BIOS, I'd advise against updating to it. Even if it's working with a DX2-66, it's somehow buggy and flaky. Not recommended. I don't see any harm in trying, but again, don't expect a 100% stable system.

Alright, thanks for quick reply!
I think i'll go ahead with at least the first update 😀

The readme is a bit optimistic here. The BIOS with integrated Video BIOS "works" on all the mentioned mainboards, but only on mainboards with onboard graphics it will work 100% correctly. On those boards it even supports Am5x85 CPUS and enables WB L1 cache.

On ISA boards without graphics chip it generates issues, on boards with PCI support, like the 486-VIP-IO it breaks PCI support completely.
If you need Am5x86 support by all means necessary, you can use it with a VLB graphics card and leave 4 PCI slots rendered useless.

Hmmm... I wanted to try updating to the bios mentioned above (3.07G), but it's not working... I get no POST when using my newly flashed chip in my 486.
I'm using the binary with 3.07G from https://theretroweb.com/motherboards/s/fic-486-gvt-2#bios and an ST M27C512 chip with a T48 Programmer.
The flashing seemed to went well, success reported... but then no POST signal when booting. With the original chip with the older bios it still works fine...
This is the first time I'm flashing a EPROM so I might have missed something...

Any thoughts?

I assume you erased the EPROM before with a UV-EPROM-eraser?

-verify in programmer its all there
-post card

majestyk wrote on 2024-04-06, 08:04:

I assume you erased the EPROM before with a UV-EPROM-eraser?

No, but it was bought as "erased" and I verified in the software before flashing that it was blank.

rasz_pl wrote on 2024-04-06, 08:09:

-verify in programmer its all there
-post card

Too me it looks fine. I suppose this is the way to verify.. I opened the bin file and chose "Verify" with the EPROM connected

Which card do you mean?
The motherboard is FIC 486-GVT-2 and the EPROM is ST M27C512

What checksum does the .rar file show? There are corrupt BIOS files on the net for some FIC mainboards that never work.
Why not get yourself a 1MB Flash ROM and program BIOS "3276gn1", you will have support for all CPUs and broken PCI doesn´t hurt your GVT2.

majestyk wrote on 2024-04-06, 13:36:

What checksum does the .rar file show? There are corrupt BIOS files on the net for some FIC mainboards that never work.
Why not get yourself a 1MB Flash ROM and program BIOS "3276gn1", you will have support for all CPUs and broken PCI doesn´t hurt your GVT2.

Not sure what you are referring to..? The downloaded bios from the site is a bin file, not a compressed file.

The 3276gn1 version seems to be very buggy, as discussed above, and not recommended