@Ken Yap - as a side note, this project is in support of my video card experiments - https://hackaday.io/project/167089-isa-8-bit-video-experiments

I think I have some 6845s in my junk^wspares box I can mail to anybody needing one for the cost of postage. 😁

@Ken Yap - thanks but i am well stocked with both 6845's and 6545's

Ken, I might want to look into purchasing a couple 6845's! It would be great to have some on hand.

@Jacob Hahn Sure just PM me to arrange. I think it should be about the same postage cost as for Europe; I sent a couple of chips there in an envelope for $3.

@Ken Yap - here is a link to my hackaday project page for the ROM tools and examples: https://hackaday.io/project/166498-pc-bios-extension-rom-tools , it's based on @SHAOS  ibm pcjr work....

In zloader.zip, a companion package to my terminal emulator package, I had an equivalent program called makerom, which could also do lzhuf compression of the payload to reduce the ROM size. If compression is not needed, prepending the signature bytes, 1's filling and generating a checksum could probably be all done by the command line tool srec_cat, from the srecord package available in all good distros, though a good reading of the man page is needed to glean all the incantations required.

srec_cat also handles input in a wide range of toolchain formats, including the well-known Intel hex format.

dandy! i'll have a look!

If you are using Open Watcom C on Linux to build ROM images, do post the steps. I'm just curious if what I did with Turbo C in another life can be redone with OWC, even though I don't have the hardware to run my VT100 terminal emulator ROM any more. Even the PCI bus is disappearing from my workhorses.

i'm actually using NASM for my ROM code stuff, but i am using open watcom for my code run from command line. i haven't tried putting any of open watcom stuff into ROM yet, i guess i could give that a try....