On a related topic, I've been considering doing a ROM mod to my 512k, which would require custom ROM chips, which you would also require if you were going to burn your own original ROMs for your 128k.
I found this thread basically doing the inverse of what you're wanting:
http://68kmla.org/forums/viewtopic.php?f=7&t=14850&p=142219&hilit=128ke#p142219
trag indicates going from a rom image to the two chips requires separating every other byte between the two. That's an easy enough program to write, I think.
H3NRY indicates a 27c512 EEPROM works with a modification, but the pins in his description confuse me. Pin 1 on a 27c512 is A15, so setting that to pin 28 (VCC) would limit the chip to half the space, which wouldn't work for the proposed problem in that thread (Plus ROMs in a 128k). The description makes a bit more sense to me, with the chip enable line, pin 20 (it could also be output enable, pin 22).
Anyway, just some related information I noticed, hopefully it helps.
I found this thread basically doing the inverse of what you're wanting:
http://68kmla.org/forums/viewtopic.php?f=7&t=14850&p=142219&hilit=128ke#p142219
trag indicates going from a rom image to the two chips requires separating every other byte between the two. That's an easy enough program to write, I think.
H3NRY indicates a 27c512 EEPROM works with a modification, but the pins in his description confuse me. Pin 1 on a 27c512 is A15, so setting that to pin 28 (VCC) would limit the chip to half the space, which wouldn't work for the proposed problem in that thread (Plus ROMs in a 128k). The description makes a bit more sense to me, with the chip enable line, pin 20 (it could also be output enable, pin 22).
Anyway, just some related information I noticed, hopefully it helps.