pmac6100 won’t boot with NVRAM present

[cuavas]

MAME version

0.280 (mame0280)

System information

Windows 10 Pro x64
Windows 11 Pro arm64

INI configuration details

window 1
mouse 1
mouseprovider win32

Emulated system/software

Apple PowerMac 6100 using the preinstalled System 7.5 hard disk image (pmac6100 mac750)

Incorrect behaviour

If a valid Cuda NVRAM file is present, the system stops at a black screen. It boots correctly when no NVRAM file is present.

Expected behaviour

The system should boot correctly with NVRAM present.

Steps to reproduce

1. Remove nvram/pmac6100/cuda
2. Start mame pmac6100 mac750
3. Allow the system to boot
4. Shut the emulated system down cleanly (Special menu, Shut Down)
5. Exit MAME
6. Start mame pmac6100 mac750
7. The emulated system will be stuck at a black screen

Additional details

I don’t know when this started happening, but MAME 0.280 shows this behaviour, as does c6b0f6a. It happens on both x86-64 and AArch64, so it doesn’t seem to be a bug in a specific recompiler back-end.

[cuavas]

@rb6502 is this a known issue? I’m pretty sure I used to be able to get it to boot without having to remove the NVRAM every time.

[rb6502]

Definitely not known.

[rb6502]

It's specific to 7.5, the original 7.1.2P doesn't show it. That gives a reasonable comparison at least.