Gameboy4iphone doesn't work on portrait mode?

I was downloading some roms for a friend of mine on his 4th gen iphone which is on 4.3.3 jailbroken with jailbreakme.com. I tried testing them out but the screen was blank and only sound came out. I tried it in landscape mode and it seemed to work. The emulator seems to work fine on my 3rd gen ipod touch though. Any ideas on how to solve this?

buy a different emulator. There are a couple of better ones.

Firmware diff??

like what? gameboy4iphone is free by the way.

GBC.emu is my favorite Gameboy/Gameboy Color emulator. It costs money, but the developer is still active and it works VERY well. It does not support GBA games, though. If you need a "preview" of how the emulator works, SNES9x EX is built on the same exact interface, but simply is an SNES emulator.

All of the zodttd emulators blow sh*t compared to the .emu releases done by another author.

I'm having trouble with the portrait mode.
black screen but has sound.
im using 4th gen ipod touch with a 5.0 jailbroken firmware