Without editing the ROM? I don't think so, no.
As for the emulator, yeah, that might be the cause. People keep getting weird issues with John GBA, so I'd suggest you to use MyBoy! instead. Maybe you'd have better luck with that. It's my go-to GBA emulator for Android.
As for the emulator, yeah, that might be the cause. People keep getting weird issues with John GBA, so I'd suggest you to use MyBoy! instead. Maybe you'd have better luck with that. It's my go-to GBA emulator for Android.