PyBLHeli is a cross-platform tool which allows you to edit BLHeli hex files without using the windows GUI. The only requirement is a unix-like environment and python 2.7.x. Simply run python pyblheli.py and you're off. Help is provided via the 'help' command. Go figure!
for usage of the BLHeliHex class, check out the example() function in blhelihex.py