System Upgrades & Enhancements
Apple //e Enhancement Kit
Consists of: 4 Replacement Chips.
Apple P/Ns 342-0304, 342-0305, 342-0265, 342-6503 or 65C02
The Apple //e Enhancement Kit makes the //e more like an Apple //c, giving it the same ROM level, and fixes some bugs in the 80 column firmware. It also comes with a new CPU, the 65C02 which has 22 added opcodes, and some bug fixes over the original, 6502. Most new software packages will require an 'enhanced' //e and will not run on the original //e.
Apple //c 3.5 in. ROM Upgrade
Consists of 1 Replacement Chip. (Cutting and Soldering Jumpers needed)
Apple P/N 342-0033
The Apple //c 3.5" upgrade lets the //c use a UniDisk 3.5" or SmartPort hard disk attached to the back of the //c. Most users can get away with a simple ROM swap and cut/solder modification, some really old //c's require a new motherboard as well, and this can be done at an authorized Apple dealer free of charge. In addition to the ability to use the 3.5" drive, other bugs in firmware have been fixed.
Apple IIgs ROM 01
Consists of: 1 Replacement Chip
Apple P/N 342-0077-B (NOTE 'B')
The Apple IIgs ROM 01 upgrade is a replacement for the original IIgs motherboard, it is not for the ROM 03, hence you can NOT 'downgrade' a ROM 03 to a ROM 01. It is not possible. The ROM 01 (or greater) is REQUIRED for ALL GS System Disk releases greater than 4.0. It fixes and adds some tools to the ROM which the system software is dependent on.
Apple IIgs VGC Upgrade
Consists of 1 Replacement 144 pin Quad Package (Special Tool Required)
Apple P/N 344S0046-C (NOTE 'C')
Fixes Double High Res fuzziness and an irregular pixel display in the lower left corner.