Official OTA Update Procedure
1) Use TWRP and make a full backup, then connect your phone to your computer and transfer the backup files to your computer
2) Reboot your phone into the bootloader, either by doing adb reboot-bootloader or the physical key combination (power off then press and hold the power and volume down key for ~4 seconds)
3) Download the Stock 5.1.0-LPA23.12-15.0 Image from here, do NOT use Motorola's Recovery Image to do this procedure, it will fail, as the hashes are not what the OTA is expecting for the system.img, and extract the contents to a folder on your computer
4) Download the OS relevant attached mfastboot zip and unzip the contents to the same folder on your computer (if you are having issues with mfastboot try reefuge's version and see if it helps!)
5) Open up a command prompt in the directory and use the following commands to flash the 5.1 Stock Image, erasing the userdata partition is not required but it is highly recommended, as you can easily restore the TWRP data partition after doing these steps if you want your personal data back
not required, but recommended! mfastboot erase userdata required mfastboot erase cache mfastboot erase customize mfastboot erase clogo mfastboot flash partition gpt.bin mfastboot flash motoboot motoboot.img mfastboot reboot-bootloader mfastboot flash logo logo.bin mfastboot flash boot boot.img mfastboot flash recovery recovery.img mfastboot -P flash system system.img mfastboot flash modem NON-HLOS.bin mfastboot erase modemst1 mfastboot erase modemst2 mfastboot flash fsg fsg.mbn mfastboot reboot
7) Download the OTA and select to install the OTA
8) Rejoice in your completed OTA update, if the update fails to install, upload the recovery logs (or tell us the problem) and we will try to help!
9) You can now install TWRP and root if desired, and restore your TWRP data backup if you erased it beforehand
TWRP System Image
The TWRP System Image can be used instead of trying to apply the OTA update, this is a backup of my own phone's system partition after doing the OTA update, so it's already on 222.27.5...
Alright, after quite a bit of time uploading...
Here is the TWRP System Image
1) Download the Stagefright System 222.27.5 TWRP backup from the above link
2) Unzip the Stagefright System 222.27.5 folder to your computer
3) Copy the Stagefright System 222.27.5 folder to your phones internal storage, to the TWRP/BACKUPS/TA0000008VJ/ directory
4) Reboot your phone into recovery (TWRP)
5) Click Restore and select the Stagefright System 222.27.5 folder
6) Verify that the System partition is selected and then Swipe to Restore
7) Clear your cache
8) Boot into system and enjoy the new patch