09455: maclc575: Fails to boot with 5MB RAM configured

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
09455	Graphics	Major	Always	Apr 29, 2026, 11:56	15 days ago

Tester	Robbbert	View Status	Public	Platform	MAME (Self-compiled)
Assigned To		Resolution	Reopened	OS	Windows (x64)
Status [?]	Confirmed			Driver	apple/macquadra605.cpp
Version	0.288	Fixed in Version	0.289	Build	x64
		Fixed in Git Commit		Github Pull Request #

Summary	09455: maclc575: Fails to boot with 5MB RAM configured
Description	This system is listed as working. At start, it produces a sound, but only a black screen. Nothing happens thereafter. Currently worked around by changing the default RAM configuration. The system has 4MB soldered RAM and a single 72-pin SIMM slot. It typically shipped with a 1BM SIMM installed. Supported RAM sizes are 4MB, 5MB, 8MB, 12MB, 20MB and 36MB, i.e. a power of two for the SIMM if installed (0, 1, 2, 4, 8, 16, 32) plus 4 for the soldered RAM.
Steps To Reproduce	>mame maclc575 mac760 It makes a sound. The screen is black. Not sure if it's a regression, as I've never tried this system before, but assuming that it is.
Additional Information
Github Commit

Flags	Regression
Regression Version
Affected Sets / Systems	maclc575

Attached Files

No.24368 AJR Developer Apr 29, 2026, 15:19 edited on: Apr 29, 2026, 15:28	Confirmed. Note that macqd605 and maclc475, both with an identical ROM definition, work OK with the same HDD images.
No.24438 Robbbert Moderator Jun 21, 2026, 13:08	Noticed just now that it's working. Whoever fixed it might want to claim credit.
No.24520 cuavas Administrator 15 days ago	It still won’t work with 5MB RAM, it’s just that the default was changed to 4MB RAM to work around the issue.