Some immediate issues I'm seeing.

1. The submodule locations should not change. If any changes are needed, they should occur upstream (not an issue for gambatte, since we control it effectively).
2. On that, why did you change SameBoy's submodule? The only change is something with upstream's Makefile which we don't use at all anyways, our provided CMakeLists is how we build SameBoy.
3. Gambatte already exposes bank registers, as part of IDebuggable's GetCpuFlagsAndRegisters. You've seemed to have "exposed" it now as some public function not associated with any interface (more or less not useful for lua and even for ApiHawk that's not particularly good).
4. Don't bother touching the old BSNES core, it's legacy and subject to be removed eventually once new BSNES has its final nits resolved.

Some immediate issues I'm seeing.

1. The submodule locations should not change. If any changes are needed, they should occur upstream (not an issue for gambatte, since we control it effectively).
2. On that, why did you change SameBoy's submodule? The only change is something with upstream's Makefile which we don't use at all anyways, the CMakeLists is how we build SameBoy.
3. Gambatte already exposes bank registers, as part of IDebuggable's GetCpuFlagsAndRegisters. You've seemed to have "exposed" it now as some public function not associated with any interface (more or less not useful for lua and even for ApiHawk that's not particularly good).
4. Don't bother touching the old BSNES core, it's legacy and subject to be removed eventually once new BSNES has its final nits resolved.

on 1: yeah ,that's an oversight on my end, looks like sameboy change has already been merged, but I haven't updated the submodule path, I'll submit a change for that. For Gambette, it's still sitting in PR awaiting approval.
2. see 1. I was having build issues and it's already merged, I'll create an update commit to update the new upstream.
3. let me play arround with that one, since I put the bank registers back into the original function to reduce changes, I may not need the other function.
4. ok, I'll revert those changes.

@CasualPokePlayer , addressed 1-4, I am tempted to revert libsnes changes as well as memory and execution breakpoints cause exceptions in libsnes for "SGB System Bus", and other domains don't seem to do anything.

I'll probably do this then ping you in channel in Discord for re-review. But let me know if there's anything in my libsnes changes that you think would be useful to keep, otherwise, I'll probably revert the libsnes changes.

ok, rolled back libsnes changes as callbacks aren't supported on supergameboy memory in libsnes or bsnes, so the change was pointless, so I went ahead and rolled it back as it was one of your action items.