07874: cobram3, cobram3a: The games only show a black screen when a NVRAM is present

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
07874	Save/Restore	Major	Always	Feb 12, 2021, 07:58	Feb 13, 2021, 18:20

Tester	Osso	View Status	Public	Platform	MAME (Official Binary)
Assigned To	Osso	Resolution	Fixed	OS	Windows 10 (64-bit)
Status [?]	Resolved			Driver	gottlieb/gottlieb.cpp
Version	0.228	Fixed in Version	0.229	Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	07874: cobram3, cobram3a: The games only show a black screen when a NVRAM is present
Description	Without a NVRAM (i. e. the first time you run them) the game work fine. If you quit and launch them again without deleting the NVRAM, they don't boot, stopping at a black screen.
Steps To Reproduce	1) Make sure you have no NVRAM file in nvram\cobram3\ 2) Launch the game - game will work 3) Exit the game 4) Launch the game again - only a black screen
Additional Information	I believe regression is https://git.redump.net/mame/commit/src/mame/drivers/gottlieb.cpp?id=b8c338858a101d14308c64c87b0f714db4f05326 The NVRAM size was moved from 0x1000 to 0x3000. At 0x1000 this game seems to use normal (work) RAM. Reducing the size of the NVRAM to 0x1000 again and putting 0x2000 of normal RAM thereafter makes the game work even with an NVRAM present. I think the NVRAM size was augmented as a shortcut to avoid creating two maps, one for games which have ROM in the 0x1000 - 0x2fff range and one for games which have normal RAM there. I don't think there are game which really have 0x3000 of NVRAM. If someone can confirm my suspicions, I'll take care of doing this with the two different maps. Originally reported by Guru.
Github Commit

Flags
Regression Version	0.227
Affected Sets / Systems	cobram3, cobram3a

Attached Files

No.18461 Robbbert Senior Tester Feb 12, 2021, 12:36	Issue confirmed by hap.