Sonic Remastered v2 incompatible

[Former user]

Original issue 405 created by Kero.Genode on 2015-01-06T08:25:26.000Z:

What steps will reproduce the problem?
1. To start rom and freeze in the black screen
2. Need disable SRAM to play, but I can't
3. This good game hack, it has nekomix themes

What version of the emulator are you using (official, SVN revision,...)?
Genesis plus gx 1.6.0 and 1.7.4, this game is funcional in pc with gens and kega (disabled SRAM)

Sonic Remastered v2 rom is availabe in sonic retro

[Former user]

Comment # 1 originally posted by ekeeke31 on 2015-01-07T07:32:12.000Z:

Why would a hack need SRAM to be disabled ?

[Former user]

Comment # 2 originally posted by Kero.Genode on 2015-01-09T10:20:50.000Z:

do not know, but if not deactivated sram not work this game, other games should not disable sram for proper operation of saved game, a strange case sonic remastered 2 by default does not save the game, but select levels with code of sonic 1 (up, down, left, right, A + start on the menu)

In kega-gens also freezes at startup if it is not removed sram, would be very grateful that sram disabled-enabled option will be added in the next review of genesis plus gx :), some other game hack also require the option

[Former user]

Comment # 3 originally posted by ekeeke31 on 2015-01-09T12:41:48.000Z:

Out of curiosity, which game hacks also need SRAM to be disabled ? I would prefer handling this automatically like with other special games than adding another optionnal setting for this.

Also, according to the changelog on Sonic Retro, version 2.0 of this hack added a saving feature. How does this work in Fusion with SRAM disabled ? Version 1.0 works fine right ? Seems odd that you have to disable SRAM in emulators after the hack added SRAM support, looks like a bug in the hack rather than a bug in emulators :-/

[Former user]

Comment # 4 originally posted by ekeeke31 on 2015-01-10T19:54:30.000Z:

I ended up looking into it and it's indeed a bug in the hack code regarding SRAM support. To sum it up, technically (just in case the author of the hack read this someday or someone wants to fix it) the code wants to initialize some SRAM value to zero if it is read > 2 but actually does the opposite. Emulators which have unitialized SRAM set to 0xFF by default (like Fusion or Genesis Plus GX) will cause the game to jump to some undefined code and go in an infinite loop)

You can bypass it by simply having a srm file all filled with 0x00 when you start the game for the first time, no need to disable SRAM (which only works by chance in Fusion). So, simply copy the .srm file above in your /saves/md/ directory after renaming it like the ROM file is named if needed. I tested it worked fine.

You could also patch the hack bug to get proper SRAM saving in game (it seems to save SRAM to some extent with the method above but I suspect this is not fully working).

Here is the action replay code to enter to get it fixed:

1D7D04:6E08

You can also enter this in Kega and see that it now works even with SRAM enabled.

[Former user]

Comment # 5 originally posted by [e-mail] on 2015-02-02T12:06:58.000Z:

Author of the hack here. Unfortunately, the hack's been abandoned around 7 years ago, and I lost its source code in a hard drive crash about 2 years ago.

It's actually kinda weird that it'd screw up in Fusion like that though, considering Fusion's what I tested the thing on in the first place (never did like Gens).