I have already looked into this.
I tried to look at what was in the firmware (you can get to the flash image with 7zip). The flash image can be viewed through a plain text editor but I am sure there would be checksum's/crc's stored in the header to detect modifications in the payload. So I wasn't game enough to start tinkering yet. If my situation becomes more desperate, then I'll look into it a bit more. However, I haven't looked into whether or not a cross-compiler exists for this processor. I sure it must.