Okay, I am trying to understand flash programming on the gba. Looking at
an intel data sheet it basically says write 0x90 to any address then read
from an address with A0 = 0 and A0 = 1

so if r0 = 0x8000000 and r1=0x90 then shouldnt something like this work:

strh r1,[r0]
ldrh r1,[r0]
( mov r0,r1; bx lr)

But I only get the bytes that were programmed into the cart by the MBV2 the
last time I programmed it...strb/ldrb doesnt help.

David