The fastboot files have been leaked for Stock ICS on the Razr M! This means you can safely try the Leaked Jelly Bean and flash back to stock to remain on the OTA update path!
To flash the Fastboot stock files
1.) Install Moto USB drivers here
2.)Grab the latest version of RSDlite 6.1.4 here
3.)Download the Fastboot file here (it is a pretty big file 648MB)
5.)Enter Fastboot mode on phone (power down phone, hold volumeup+volumedown+power until the menu shows up, use volume down to highlight AP Fastboot and press volume up to select it, do this quickly or phone auto reboots)
6.)Connect phone to PC
7.)Select your phone XT907
8.)Click the "..." then select the fastboot file that you downloaded
9.)Then select uncompress and flash
The whole process may take up to 15 minutes so don't freak out.. in fact just walk away and come back.
Grab the Fastboot files Via XDA