Put the firmware into U disk Root directory, Insert the USB disk to TV USB port, There is 2 way for upgrade
1. Go to Factory Mode(menu + 1201), upgrade - USB upgrade, It will restart and upgrade.
2. Plug off the power cable , press and hold the Power touch button on the glass, Plug in the power cable. It will upgrade.
The LED light will flashing during upgrading don't power off the cable. When the upgrading is finished, the LED light will stop flashing.(It require a touch key board)
If the screen is reversed after upgrade firmware, please ask AVEL for another version firmware. It can't be changed in factory mode.
Adjust the brightness to Maximum
Go to Factory Mode(menu + 1201), Picture -- Picture Mode -- Backlight -- 0 or 100 for maximum (The default is 100 but sometimes 0 is maximum so it depends on different panel case by case)