01-25-2021, 08:45 PM
It is an official Apple mod. They provided updated ROM chips with instructions to cut a specific connection and solder bridge another one:
https://apple2online.com/web_documents/a...lation.pdf
There are differences in how the serial port is handled between the original ROM255 and all later ROMs
https://wiki.68kmla.org/Apple_IIc#Revisions
But I don't know if that would cause the hangup problem.
https://apple2online.com/web_documents/a...lation.pdf
There are differences in how the serial port is handled between the original ROM255 and all later ROMs
https://wiki.68kmla.org/Apple_IIc#Revisions
But I don't know if that would cause the hangup problem.