Hi,

As you do not report compilation/assemble errors I'll assume there are none.

In theory it shouldn't matter which assembler you use - with the proviso that it understands the syntax produced by the compiler.

Have you compared the two hex files? You should have one changed byte and a couple of changed checksums.

How sure are you that you are using the correct version of the compiler?

Yes its possible to change a byte in a hex file, the format is well documented. I beleive there is a overall checksum and one for each line.

What variables affect the generation of the .hex file by MicroCode Studio
All the variables.

Does you source include the fuses used for flash programming? If not I guess you manually enter them into your programmer?

Does your programmer allow you to make modifications?

Personally, I wouldn't even try to change the hex file, I'd find out whats wrong.

George