BizHawk GB/GBC Cross Version Sync

Notes for keeping GB/GBC TASes syncing in newer versions of bizhawk+gambatte

TASes on versions before 2.2.2 are basically the wild west and may need drastic resyncing to the point of rewriting the TAS.

.bk2s are just zip archives and can be hand edited to update sync settings per below:

All TASes are verified on GBA hardware because of its use in the Game Boy Player/GBI, which is equivalent to GBC hardware except for a slight BIOS edit which makes GBA detectable. This was called "CGBinGBA" in SyncSettings.

2.2.2: Known to verify perfectly with Pokemon Red/Blue

2.3: Known to sync with all of Pokemon Gen 1

2.3.2: Verified to sync with all of Pokemon Gen 1 and 2 including RTC in Gen 2 when adjusted for per-cart clock drift

Between 2.4.1 and 2.5.0, GB/GBC games outside of Pokemon begin verifying nearly universally.

2.5.0+: Now must use "EnableBIOS" : true in SyncSettings and provide a copy of the agb variant of the cgb BIOS in firmware

2.5.2+: "CGBinGBA" dropped in favor of setting ConsoleMode to 3

2.6.2+: Need to add 14 frames for the GBA modeswitch to the beginning of any movies made prior to 2.6.2 and when dumping in 2.6.2 for console you no longer need to account for the modeswitch in the dumpscript. This may break movies with ELF "on", though it's advised to use ELF "off" anyway.

Known issues:

Wario Land II encounters an extremely rare hardware quirk that is not fully implemented. The GameBoy blocks reading of VRAM during each line until the hblank period. If you attempt to read VRAM at a specific range of addresses on the exact cycle of the handoff to hblank, you can read undefined values other than the blocked FF and the intended contents of VRAM. This was only seen in glitched runs for some reason.

Tokyo Disneyland and Daiku No Gen-San (Hammerin Harry) rely on unimplemented open bus reads from SRAM (which is similar to the Wario Land II issue except in the SRAM domain instead of VRAM).

Games with obscure mappers are often unsupported or inadequately tested such Robopon and its Huc3 mapper.