This Avvio 781S firmware (stock ROM) will help you easily un-brick and restore your device to its default factory state. If you have previously rooted or modified the system (or other) partition of the phone in any way, flashing this stock ROM will overwrite all existing modified system files to replace with factory software.
If you have important data on the phone (like contacts, messages, app data, etc), please back them up because you could loose data after flashing.
Charge the phone to at least 50% so that the flashing process will not be interrupted by low battery. Interrupting the firmware installation means bricking your phone.
Download the firmware file from the link below and follow the recommended flashing instructions immediately after the download options. Please report any broken links discovered.
Download Avvio 781S flash file
|AVVIO 781S UNI_C421_brightstar_1.2_150711(new).rar||Download||464 MB|
Important! Always backup existing firmware before flashing any firmware.
How to flash
After downloading firmware from above link, extract the contents of the archive to an empty folder on your computer. Get a functional USB cable, then follow the instructions via this link to learn how to flash the firmware.
If you have any questions or other contribution please post in comments section for assistance.