I have a feeling what may be causing ROMs to vanish. MOS 3.50 writes to sockets 4-7 during a power on reset (actual or simulated) to clear them, an annoying feature that I removed in my Multi OS. If the EEPROM device is the AT27C256-based one I think it is, a Write operation causes it to provide invalid output data for about 1ms. Therefore when the MOS checks for a valid copyright string it may not be able to find it and flags the socket as empty. I say 'may' because the CMOS configuration can affect the boot up time. Assuming two service ROMs in 6/7 you could try the following;
?&2A7=&82 : ?&2A8=&82
and see if the ROMs reappear. Alternatively, try removing the WI link on the EEPROM module (Write Inhibit) as this will block any attempts to write to it.
?&2A7=&82 : ?&2A8=&82
and see if the ROMs reappear. Alternatively, try removing the WI link on the EEPROM module (Write Inhibit) as this will block any attempts to write to it.
Statistics: Posted by ctorwy31 — Wed Jan 15, 2025 11:19 pm