First step for Installing Rom 

1. Download And Install Motorola Usb Driver
2. Download and Install RSD Lite motorola Flash Tool

How To Install ROM Motorola Droid RAZR M XT907

1. Extract the firmware in the zip file to your computer, open the extracted folder.
2. After extracting you will see a xml file “VZW” then open the file with notepad. Remove all lines with the word “getvar”, there were two lines that have the word “getvar”, then save.
3. Open RSD Lite, press the “…” next to the filename. Find and select the xml file that has been edited in step No.2.
4. Since all data saved in phone storage will be wiped, you should backup contacts, sms, calendar and call log. If you already rooted you can also backup installed apps + data using MyBackup or Titanium Backup.
5. Your phone must be on the AP FastBoot Mode.
6. Turn off your phone.
7. Press and hold the Vol Up + Vol Down + Power button together.
8. You will enter into the Boot Mode Selection Menu, scroll down and select AP Fastboot.
9. Flashing process will take about 15-20 minutes.
10. If the flash is successful, your phone will reboot and revert to the stock firmware.