I beleive there might be a compatability issue with the Apple IIgs ROM 3. I beleive this might have to do with the expanded main board RAM, but I do not have the equipment (A IIgs ROM 1 or IIgs ROM 0) to test this with. Here's what I've done to knock on the problem though.
My normal operating configuration is the Apple IIgs ROM 3, with Slots 1-2 set to the defaults, Slots 5-7 set to "Your Card", the CFFA3000 in Slot 7, and an Apple IIgs Memory Expansion fitted with 1MB of memory. Starting out, my CFFA3000 firmware was v3.0.2. I have since upgraded to v3.1.
The problem first appeared as flakiness of native IIgs software. GS/OS runs normally, but some memory intensive applications cause a crash. Wolfenstein 3D and MODzap are the two that are flaky and will generally crash.
My first suspicion was the 1MB Apple memory epansion board. I removed this board, which made further testing impossible since both Wolfenstein and MODzap would run out of memory.
I downloaded disk images of both MMT, and the Apple IIgs Dealer Diagnostics (v3.0). I tried MMT first, but was disappointed that it only tests the memory expansion, and not the on-board RAM. It also indicated that the expansion board was fine. I then ran the Apple diagnostics, and the RAM came back fine. For kicks, I ran everything that didn't require loopback plugs. This is when things got strange -- it dropped to the monitor (star prompt) during the "Serial Internal" test, which exercises the Slot 1/Slot 2 serial port hardware. This was special in that a Control-OpenAfter that, I whittled down the test sequence to "Main Board RAM" then "Serial Internal", which crashes the system (drops to the monitor) reliably.
In the process of whittling, I removed the memory expansion board, set the slots to defaults, and then set them all to "Your Card" with the CFFA3000 in Slot 7. I also tried the CFFA3000 in Slot 1, set to "Your Card" with the same results.
At this point, I thought I might have bad main board RAM, despite getting passing marks. At this point I pulled an additional Apple IIgs ROM 3 from storage, installed the CFFA3000 in Slot 7, checked that this slot was set to "Your Card" and verified that it presented the same behavior.
Here's an example of the drop to monitor:
E1/4100: 00 58 BRK58
A=5800 X=1A02 Y=0000 S=01C4 D=0000 P=04 B=00 K=E1 M=00 Q=00 L=0 m=0 x=0 e=0
*
My new working theory was that I might have a bad disk image, or that the CFFA3000 was the source of the issue. I proceeded to attach an 800k drive, enable the controller, and copy the disk image to the 800k floppy. I pulled the CFFA3000, and booted from the floppy. The same test pattern no longer produced the error, nor did a full test.
Reinserting the CFFA3000, even unused, produced the error.
Anyone know what might be going on, or have any theories?
-Lucyen