Walton Primo H3 4.4.2 firmware
Primo H3 4.4.2 Driver, flashtools & firmware (Bugfixed) Download Link:
Primo H3 4.4.2 Firmware (Bugfixed Version) upgrade instruction
1. Install driver.
1st step: Power Off the phone and Connect your phone with PC via USB cable. Now go to My Computer>Manage> Other devices> MT65xx Preloader