-Make sure you have the charging cable connected to the phone and the cable to an outlet not an computer.
-While in the ap fastboot screen with the low battery problem, just push & hold Vol - and Vol+ and power buttons at the same time for 10 seconds
-Then IMMEDIATELY press and hold Vol - and Vol+ for 10 seconds to get back to the boot menu.
-Then once in the boot menu go down the the one option that has the word tools on it which is the last one.
-If it does not do anything just press volume up or down and go back to the tools and click power (enter) again.
-Then you should be boot to the M logo.
-Then after a bit you will be presented to an battery icon charging your phone!
-After a good charge up to 50% or so download the program called
-Download that program and make sure your phone is back in AP fastboot and your battery should say OK meaning you can now program again.
-From there run the Droid RAZR Utility you just download it and choose option 1 and let it do its thing.
-Once done you should have the original stock rom and if you had root you must re-root it.
-Please message back for any questions! I am happy to help because I know how frustrating this is!