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	1 hour 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	0.289GIT	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 1 hour 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.