Hi all. I've been working on one of these. It has a CNC BIOS on it that won't let me boot like a normal BIOS does. I'm trying to find a copy of a standard BIOS for this...

https://theretroweb.com/motherboards/s/trang- … -headland-ht12a

Per Horun's suggestion I tried a standard HT12 BIOS with no joy. I get the 'BIOS Checksum 27256' error (the video BIOS boots fine obviously). This error I get when I boot to BIOS' using EEPROMs I burn myself. The first question is: would this error be from corruption on the newly burned BIOS chips? I should note that I'm new at burning my own BIOS chips, and it could be that I'm using the programmer wrong. I usually just load the bios into the burner software using the 'Normal' setting. It seems to program fine.

Assuming that's not the issue, I tried a couple different BIOS with no luck, the same error (or no response at all). I guess I need to understand what exactly the checksum error means - bad chips or images, or that the chip/image is fine but won't work with this board.

Also, I notice that it's hard to find the AT28C256 chips now. I have W27C512 chips as well. I was wondering if that would be an adequate substitute for the other (28-pin package). If not are there other more common chips that can be recommended? Maybe ones in the smaller PLCC format with an adapter?

Thanks for your time all.

PS: Hi/Lo .. Odd/Even... does Odd correspond to Hi or Lo?

EDIT Adding: the software I use to program the chips is XGecu.