Batman Returns Sega/Mega CD - Screen stays black with option "Plattform only"

[Former user]

Original issue 312 created by gora.patrick on 2012-12-09T20:11:51.000Z:

What steps will reproduce the problem?
1. Choose gametype "Plattform only" in the Options menu
2. Start the game

What is the expected output? What do you see instead?

The game should start with the first plattform level.
Instead the screen stays black and the main menu music plays.

What version of the emulator are you using (official, SVN revision,...)?
1.7.3.

Tried both, the US Version (from the net) and the EU Version (ripped from my own copy). I've attached the cue file from my EU Version. Ripped with IMGBurn.

[Former user]

Comment # 1 originally posted by ekeeke31 on 2012-12-09T22:09:50.000Z:

[Former user]

Comment # 2 originally posted by ekeeke31 on 2012-12-09T22:18:44.000Z:

Will need to investigate about it.
In the mean time, if you could tell me if this in ever worked (in 1.7.0 or in 1.7.1), this could help figuring what is causing this.

[Former user]

Comment # 3 originally posted by gora.patrick on 2012-12-10T17:14:34.000Z:

just tried it in 7.0 and 7.1 and in both it's broken already.
Just tried both isos with fusion 3.64 and it just works fine.

[Former user]

Comment # 4 originally posted by ekeeke31 on 2012-12-10T19:26:20.000Z:

It appears this was caused by a bug in the game... and my implementation being not robust enough against this kind of bug.

For the record, MD side was attempting to write to a read-only register and this ended up corrupting the register on SUB-CPU side. Ignoring writes to read-only registers on MD side fixed it.

Fixed in r757