rebuild Mighty 1284P bootloader

Hi, all readers.
I want to rebuild the bootloader,
I have put the files in the ‘hardware’ off my sketches directory. (XP)
But on the i have errors about missing path
make <e=3> error 3,

Thx

Do you have AVR tools (eg WinAVR) installed?
You'd have to take some extra effort to use the Arduino-included tools, because they won't end up in your path unless you put them there.
Optiboot has some makefile modifications to allow builds using the Arduino toolset, but you'd still need a command like:

     ..\..\..\tools\avr\utils\bin\make OS=windows ENV=arduino atmega1284

(or use the provided "omake.bat atmega1284")

Placing the files in the sketch/hardware dir, gives error, even with omake.
Placing the files in de arduino/hardware dir, then omake works, but the hex files is different from the org files in from git

You will definitely get HEX files that are different. The HEX from github is compiled with gcc 4.6.3 (I think) or 4.7.0. It's safe to assume you're using a different version. So the output will be different. Should still work if it compiled without errors.