I was working on repairing a CRT for my IIgs today, and was using the video patterns on the diagnostic disk. Once I was satisfied with the monitor, I figured why not run the whole suite of tests for grins.
Everything passed, except the ADB mouse test. It just says it failed and to refer to the service procedures. Except if I boot up GSOS, the mouse works perfectly fine. The keyboard passes it's test no problem.
Does anyone by chance know what exactly it's trying to test? And more importantly, why it's failing a mouse that is infact working?
Figured it out. I forgot that I had my Phasor clone card in slot 4, and had changed the control panel to "Your Card". Changing it back to the built in mouse allows it to pass. Odd that GSOS can read it fine when set to "Your Card" but the diagnostics can't. But I'm sure there probably is an explanation for why that is the case. Guessing some difference in the way GSOS accesses the hardware.
ROM 03 can allow mouse and "your card" at the same time, rom 01 cannot, unfortunately. This may relate to what you're seeing.
It is a ROM 3 and it failed when set to your card.
Can you find a way to test another mouse and see if it does the same thing?
I have an ADB touchpad. Same behavior. Your card results in the diag failing, but works in GSOS. Setting back to mouse passes the diag.
At this point it appears to be a difference in the way the diag/ProDOS accesses the hardware vs how GSOS does.
I would try something that uses the mouse that is non-GS specific like runs under ProDOS 8 like Dazzle Draw or MousePaint or something. If it works with that, I just wouldn't worry about it. Is this all something that you just noticed or something that changed? If you haven't seen different behaviour before, this might just be how it is, and the diagnostic software just produces slightly wrong results.
It makes slot 4 on a ROM-01 IIGS the perfect place to stick a Uthernet II card in. That way you can have your slot-4 cake and eat it too.
On my ROM-01 I have a mockingboard, which a lot of 8 bit stuff expects in slot 4. I can use slot 3 for the uthernet though (have only used it briefly but it worked).
It's not a huge deal for me to have to hit the control panel to toggle between mouse/mockingboard though, since I don't use anything currently which uses both. If that changes most likely that would be music software which hopefully lets me change slot config.