My guess would be that it's a mask ROM or OTP version of 27C1001, if you won't succeed reading it externally, try dumping BIOS from a running machine with "DUMPAT" or "GETROM" programs.

Try NM27C512@DIP28. Also it could be a larger chip with padded or mirrored firmware.

When you read the eprom with Check ID checked, what is the error given in hex code ? You can hex search thru InfoIC2Plus.dll to see what the ID says it is...
or check against this older database...

If you just want the bios
https://theretroweb.com/motherboards/s/pcchip … 2-v1.7-486#bios

SSTV2 wrote on 2024-12-03, 00:53:

My guess would be that it's a mask ROM or OTP version of 27C1001, if you won't succeed reading it externally, try dumping BIOS from a running machine with "DUMPAT" or "GETROM" programs.

Thanks, this worked to get the BIOS! I couldn't find GETROM, but I found DUMPAT which dumped a 1MB region including the BIOS. I made sure to set BIOS shadow to disabled in the BIOS settings first and ran it in conventional mode.

I also tried NSSI which dumped just the 64KB BIOS which saves some time.

myne wrote on 2024-12-03, 03:13:

If you just want the bios
https://theretroweb.com/motherboards/s/pcchip … 2-v1.7-486#bios

Haha, thanks, I forgot to check the BIOS page for the v1.7 version... oh well, it was good practice to get my own copy!

kmeaw wrote on 2024-12-03, 01:29:

Try NM27C512@DIP28. Also it could be a larger chip with padded or mirrored firmware.

It didn't work unfortunately, but led me to notice something interesting - the NM27C512 showed a red X on 27 pins, but the AT29C512 shows just one, and the error message is different. Maybe the AT chip is more similar in layout.

Horun wrote on 2024-12-03, 01:55:

When you read the eprom with Check ID checked, what is the error given in hex code ? You can hex search thru InfoIC2Plus.dll to see what the ID says it is...
or check against this older database...

Is there a certain place this will appear in the Xgpro software? I didn't notice any hex codes when ID Check or Read operations. This was the log output for my latest test:

1NM27C512 @DIP28
2  Memory Size : 0x00010000
3Pin Detected ERROR!

Cosmic wrote on 2024-12-03, 03:32:

Haha, thanks, I forgot to check the BIOS page for the v1.7 version... oh well, it was good practice to get my own copy!

I just googled the bios string.

Cosmic wrote on 2024-12-03, 03:32:

Is there a certain place this will appear in the Xgpro software? I didn't notice any hex codes when ID Check or Read operations. […]
Show full quote

Horun wrote on 2024-12-03, 01:55:

When you read the eprom with Check ID checked, what is the error given in hex code ? You can hex search thru InfoIC2Plus.dll to see what the ID says it is...
or check against this older database...

Is there a certain place this will appear in the Xgpro software? I didn't notice any hex codes when ID Check or Read operations. This was the log output for my latest test:

Copy code to clipboard

1NM27C512 @DIP28
2  Memory Size : 0x00010000
3Pin Detected ERROR!

If you get a pin error, no you will not get a ID check. You only get one if the eprom you choose is close to what it really is (power, gnd, address, etc).

myne wrote on 2024-12-03, 04:15:

I just googled the bios string.

Now just to get an image written back, haha. It will be cool to test out the AMI versions. I'm hoping the board will accept a regular 28-pin chip as I have some of those around

Horun wrote on 2024-12-03, 04:22:

If you get a pin error, no you will not get a ID check. You only get one if the eprom you choose is close to what it really is (power, gnd, address, etc).

That makes sense, thanks Horun. I'm running some benchmarks now but tomorrow I'll probe the socket for details

Stop trying DIP28 presets lmao that will never work

27C010

yeah. From archives both the m912 and m919 used OTP eprom and old website say "suggest you to burn the new BIOS file into a new EPROM and replace your current BIOS".
No flash programs are given for them. I checked my m919 w/dip32 and got a id code E542 which is not in the 866 database or .dll for a dip. My m912 have 28 pin.
Using Winbond W29ee11 per archive as replacement for the m919, used 866 and unchecked "pin" and "id" and was able to read some contents which does match TRW bios AMI 10/10/94 core.
"(for SST PH29EE010, Winbond W29EE011 flash ROM)".
Not saying your 32pin is same as on the m919 but it is not common to m912.....

29-series EEPROMs are incompatible with AMI "windows" BIOS for this motherboard, use 27-series instead. For details read this thread: PC Chips M912 BIOS update for Am5x86 and Cyrix 5x86

maxtherabbit wrote on 2024-12-03, 13:54:

Stop trying DIP28 presets lmao that will never work

27C010

Yeah, it was silly hope that maybe one would work 😂 thank you for the suggestion though

analog_programmer wrote on 2024-12-03, 16:46:

29-series EEPROMs are incompatible with AMI "windows" BIOS for this motherboard, use 27-series instead. For details read this thread: PC Chips M912 BIOS update for Am5x86 and Cyrix 5x86

Thanks for the link, this looks like it will get me on track. I just need to do some reading on the different ROM types to get a better understanding, I've been fortunate that everything I've worked with has been simple EEPROMs so far

Wait till you come across uv erasable

myne wrote on 2024-12-03, 22:26:

Wait till you come across uv erasable

I'm looking forward to it! It would be awesome to beam some UV radiation into your retro PC before flashing your carefully modded BIOS image. "In my day we used the sun to clear our BIOS, kids these days just press a button" 😂

Cosmic wrote on 2024-12-03, 22:50:

myne wrote on 2024-12-03, 22:26:

Wait till you come across uv erasable

I'm looking forward to it! It would be awesome to beam some UV radiation into your retro PC before flashing your carefully modded BIOS image. "In my day we used the sun to clear our BIOS, kids these days just press a button" 😂

🤣 and sometimes it took a few a days of bright sun to erase 😀

Hello, a few days ago I bought a tower with this PCCHIPS M912 v1.4 motherboard and today when I took it apart and looked at the BIOS chip I found that it says: 912.8-1. The thing is that while searching for information about this chip I found that on The Retro Web there are 1.7 motherboards with the BIOS chips without the sticker and with a serial number, but they are 28 pins, can someone confirm if these chips are valid for my motherboard version 1.4 or is the 32 pin chip on my motherboard compatible with any of those that come from TRW?

Tigre978 wrote on 2025-03-22, 21:38:

Hello, a few days ago I bought a tower with this PCCHIPS M912 v1.4 motherboard and today when I took it apart and looked at the BIOS chip I found that it says: 912.8-1. The thing is that while searching for information about this chip I found that on The Retro Web there are 1.7 motherboards with the BIOS chips without the sticker and with a serial number, but they are 28 pins, can someone confirm if these chips are valid for my motherboard version 1.4 or is the 32 pin chip on my motherboard compatible with any of those that come from TRW?

This one marked as "912.8-1" is the factory OTP-PROM (one-time-programmable) chip. Mine was with 32 pins, 128 KB in size and containing both AMI and Award BIOSes for this PCCHIPS M912 motherboard (they can be switched by jumper JP2 + clearing CMOS). I've replaced the factory OTP-PROM chip with Winbond W27C010 EEPROM which is compatible with AMI BIOSes, 'cause it turned out that newer W29EE011 chip only works with Award BIOSes for this mobo.

My motherboard has a 32-pin chip, but instead of an AMI BIOS it uses Award, and I need to know which chip would be compatible with this motherboard. Is the W29EE011 chip you mentioned compatible with my motherboard?

Tigre978 wrote on 2025-03-23, 14:12:

My motherboard has a 32-pin chip, but instead of an AMI BIOS it uses Award, and I need to know which chip would be compatible with this motherboard. Is the W29EE011 chip you mentioned compatible with my motherboard?

As I already wrote, Winbond W29EEo11 will only work with Award BIOSes for this PCChips M912 mobo. Mind that W29EEo11 chip is 128 KB in size and M912 BIOSes are 64 KB, so you'll probably need to copy the BIOS image file twice in this EEPROM. Or you can use W29EE512 EEPROM instead which is 64 KB in size.