Now, I'm sure you've been told many many times that gba emulation on the nds is impossible well this is entirely untrue. It is however impossible to software emulate the gba on nds well at any descent frame rate anyway. It is possible to create a hypervisor using the mpu that translates the writes to the graphics and sound hardware of the gba to the nds hardware this however is hard to do which is why no one has done it well except for someone who will not under no circumstances release it because he does not condone piracy. Using the hypervisor approach you can get full speed, maybe even faster, not to mention you could potentially add things such as save states etc but first someone would need to create a hypervisor and release it to the public. I will not be creating a hypervisor but i thought i'd let others know that running GBA games from slot1 is not entirely impossible its just no one has bothered to code something that the nds hardware does natively and release it to the public.