execute the script calling it like this :

/var/patchME XX XX XX XX XX XX

The XX XX XX XX XX XX is the desired MAC ADDRESS. Do not use colons to separate the bytes.
example:

This is ok --> /bin/patchME 00 09 34 21 21 21

This is not ok --> /bin/patchME 00:09:34:21:21:21

Congratulations ! Mac address permanently changed.