I must be going blind because I can't even see any consecutive 0xFFs to speak of any more.
I don't have a .hex file, I just edited the C code in spots to change 0xFF to 0x00.
However all you really need to do is, if the .hex file has line(s) near the end with completely 0xFF, just delete them. Can you provide a link to the file you are trying to use?