Wow, you guys are freaking me out!
I must be completely confused about how these Roms work...
In my experience, the Checksum is a value that the target processor reads back to the originator (usually over a serial interface) after performing a copy to verify that the destination file matches the source file.
So the way I understand it is that you need to have a final ROM.bin file, calculate the Checksum, transmit the file to the target, target calculates local checksum, if the two checksums (Xmt/Rcv) match, Copy complete & error free.
What am I missing?
You cant mess with the digital data in a file and expect the checksum to be the same.