Recover Solution #1 (Wipe cache, this will clear app setting data but will retain user data)

Go to recovery by holding power button + volume down

Choose English

Choose ‘Wipe data and cache’

Choose ‘wipe cache’ (This will only clear app settings data, other data on the internal storage will not be erased)

Choose ‘Yes’

Choose ‘Reboot’

Solution #2 (Wipe data and cache, this will clear app setting data and erase user data)

Go to recovery by holding power button + volume down

Choose English

Choose ‘Wipe data and cache’

Choose ‘Wipe data and cache’ (this will clear app settings data and erase internal storage data)

Choose ‘Yes’

Choose ‘Reboot’

Solution #3 (Adb sideload ROM file)

Download vx.y.z ROM from OnePlus support website (http://downloads.oneplus.net)

Turn off device and boot into recovery mode (By holding power button + volume down)

Choose English option

Choose Install from USB option in the recovery screen

Tap OK button.

A screen with “You are in sideload mode” will be displayed

Connect your device to PC (PC / Mac must have adb pre-installed)

Run the following command

For windows: “adb sideload <filename>”

For Mac: “./adb sideload <filename>”