Hi,
After i got the 7D, i wanted ML, for video production, and i updated to 2.0.5 firmware from canon, which i regret to, because ML for 7D is only for FW2.0.3, but i found a way to degrade the firmware from 2.0.5--->2.0.3.
1. Just
download the original Canon 7D update ( 2.0.3 ), from their webpage.
2.
Format your CF card,
charge your battery to 100%, my new battery used over 50% of it for "updating" it, so i recommend you to charge it.
3. Then when updated to 2.0.3, format your card, move these files

over to your CF card an "update" your firmware.
4. Your'e done and MagicLantern is installed on your 7D, but! You'll have to "update" it with the ML files every time you want to use it, and if you format your card, it will delete ALL your files, including ML files, so if you format your CF card, you'll have to move the MAGIC.fir and ML.zip into the CF card again, but it would'nt take a too long time.
I am not responsible for any damage too your camera, i've done this 4 times before with both 5D and 7D, and never failed, so it is easyGood luck, and wish you the best...
Best Regards,
Stian Aarrestad,
fotografstianaarrestad.com