: Power off your phone completely. Hold the Volume Up + Volume Down buttons simultaneously and connect the USB cable.

If your phone requires an authentication file ( .auth ), it will trigger RAM exceptions when unauthorized flashing is attempted.

Using a version too old or too new for the device's chip.

, which both share the "dandelion" codename but have different RAM settings). Use a Modified Download Agent

You must flash the exact same version or a newer version of the firmware than what is currently on the device. Check your device build number in recovery mode and match it with the firmware you are downloading.