All Moto X device owners can now install the unofficial stagefright fix on their smartphone via modified Brazilian OTA firmware, with due credit to XDA Developers' senior member, mastarifla, who has created new library files with the patch for the latest Brazilian OTA. Furthermore, the modified firmware has been tested and confirmed to work fine on T-Mobile variant of Moto X.

As mastarifla reports in his recent post on XDA forum, the library files have not been tested with KitKat. Hence, you need a Moto X running on Android 5.1 Lollipop for this fix to work properly.

Here is the complete step-by-step guide to install the Stagefright fix on your Moto X:

  • Ensure that your Moto X is rooted
  • Take a backup of the stagefright files (30 total) to a safe location on your phone's SD card
  • Download the to your phone or PC and extract the library files
  • Copy or overwrite your current library files in the system/lib folder with these patched lib files
  • Verify that the permissions are set to rw-r-r (644) for each library file
  • Reboot your phone (or soft reboot if you have Gravity Box installed)
  • Double-check by opening any stagefright detector app and see if it has been fixed

[Source: XDA]