Custom ROM for the Apple //c and //c+

Now, what about the custom ROM then?

ROM 4X and 5X are enhancements to the Apple //c (4x) and Apple IIc+ (5x) firmware ROMs.

It adds the following features to the Apple //c and IIc+ firmware:

Identifies and reinstates a bootable (it must have something that looks like a boot block!) RAM disk from battery-backed expansion memory (see below), such as the RAM Express II+ from A2Heaven.

Provides a menu of various tools upon pressing CTRL+CLOSED-APPLE+RESET (or holding CLOSED-APPLE when powering up), that let you:

*Enter the monitor unconditionally.
*Reboot the machine (enter standard boot sequence).
*Zero the RAM card, in case it is corrupted.
*Execute the machine and RAM card diagnostics.
*Tell the machine to boot the SmartPort, the internal floppy drive, or an external floppy drive.

IIc only:
*The system drops to BASIC if no bootable device is found (this is the default behavior in the IIc Plus).
*Configure default boot device by saving a file on the RAM Disk.

IIc+ only:
*Menu control the built-in accelerator.
*Accelerator settings persist across resets.
*Build option to default the system to 1 MHz.

This firmware enhancement identifies a ProDOS boot block on the RAM disk and, if found, restores the appropriate screen holes to make the RAM disk bootable and prevent firmware or ProDOS from re-initializing it.



It is easy to install. Just open the case and lift the original firmware ROM-chip from it’s socket, with tool of your choosing and insert the newly made ROM (EPROM) in same socket.


I also installed an never used, Applied Engineering RamExpress to my Apple //c+ as the unit was opened. The card originally had 256k RAM (soldered) so i added some more. I was able to find from my stash just two (original) sets of (8 chips per set, 256k) “Apple II 256k Memory Expansion” boxes. Those were sealed but really they are ment for using so i had no ethical issues opening them. I could possibly lift some RAM from i.e. slinky //e RAM-card but that could be done later. Or most likely, i’ll replace this card with modern version, like A2heaven’s “Apple IIc RamExpress II+” that is the good option for the //c and //c+ users right now.

RamExpress installed:

My Apple //c+ now holds some modern upgrades:

-Universal Powersupply (from Mark Wise)
-VGA-adapter (
-Applied Engineering RamExpress (768k RAM) 
-FloppyEmu w/adapter (first rev.)



All these features are very welcomed to //c and //c+ users. For //c+ users, setting the CPU to 1 MHz even after reset is very handy when you want to keep the speed at 1 MHz. This is BIG plus feature. The annoyance of choosing the speed after every reset is infernal when you need to remember to do that!

Boot-control is really nice, there’s different needs for different media and options so choosing it from menu is so much more convinient. Loving this bigtime!

The RAM-card options are handy if you’re using one. 

This is everything in one place upgrade and absolutely MUST for //c+ users. Wonder what else there might be what could be accessed and configured?

More information & ROM-file downloads:

FinApple 2018 (c)
Apple II forever.