Assuming you got them from here: https://tobylobster.github.io/rom_library/ - make sure you pick known good ones for testing with. And that is the best place to get ROMs.
The easiest way to test a ROM image is to load it into sideways RAM and/or test in an emulator. If it works, it will probably work when written to an EPROM (some do expect to be installed in sideways RAM, but they're very much the exception).
Make sure the C64 is definitely writing all 16 KB and there is no translation step occurring at any point in the process. If Wordwise Plus (a 16 KB ROM) does work then presumably not, but if you haven't tried transferring a fresh Wordwise Plus image rather than reusing the one read from the EPROM then that would be worth doing.
If the ROM isn't working once installed, save its contents using something like Rom Tool (http://www.boobip.com/software/rom-tool) and compare the contents of the saved file to the original ROM. This won't give you any more clues if they're identical, but it will eliminate some possibilities.
--Tom
The easiest way to test a ROM image is to load it into sideways RAM and/or test in an emulator. If it works, it will probably work when written to an EPROM (some do expect to be installed in sideways RAM, but they're very much the exception).
Make sure the C64 is definitely writing all 16 KB and there is no translation step occurring at any point in the process. If Wordwise Plus (a 16 KB ROM) does work then presumably not, but if you haven't tried transferring a fresh Wordwise Plus image rather than reusing the one read from the EPROM then that would be worth doing.
If the ROM isn't working once installed, save its contents using something like Rom Tool (http://www.boobip.com/software/rom-tool) and compare the contents of the saved file to the original ROM. This won't give you any more clues if they're identical, but it will eliminate some possibilities.
--Tom
Statistics: Posted by tom_seddon — Thu Mar 27, 2025 10:41 am