[quote="noeska"]I think al that is needed on how to modify free pascal for the gba is written here: http://linux.gbadev.org/gcc-gba/ .

The important part is crt0.s as this defines the gba (cartridge/executable) header. But even more improtant is the lnkscript that is used. As that glues together the crt0.o with your applicton .o file in a special way. Without that ]

im pretty sure the gba supports both thumb and arm instruction sets

iirc due to bus issues thumb is faster when running from cart but arm is faster when running from ram.