Apple IIc Upgrade ROM
The Apple IIc ROM can be upgraded to ROM version 0, 3, 4 or 04X
Version:
- 0 – This version eliminated the option for booting from drive #2, but added support for Smartport disks. The most common of these was the Unidisk 3.5
- 3 – Version 3 accompanied a logic board change, making it possible to expand the IIc’s memory.
- 4 – Version 4 corrected some bugs present in version 3.
To check which ROM version you have in your Apple, press Control + Reset. At the basic prompt type:
PRINT PEEK (64447)
The result will show which version you have:
- 255 Original
- 0 SmartPort /Unidisk 3.5
- 3 or 4 Memory-Expansion IIc
When ordering the ROM upgrade please specify which version you me to burn:
-
ROM 00 – 342-0033-A
- ROM 03 – 341-0445-A
-
ROM 04 – 341-0445-B
-
Community enhanced ROM 04X
The ROM will be written to a 27C256 chip which will need to replace the existing ROM installed in your Apple. You will also need to do a hardware modification to the Apple as the new ROM’s are 32k in size and require jumpers to be set.
– Cut jumper W1 (Make sure jumper is cut. Test continuity with DMM is possible)
– Solder bridge over jumper W2
