請使用 Factory image
Factory image: 刷回原廠 非原廠rom,手機完全壞掉用
OTA image: 原廠系統更新包(only升級) 資料不會不見(over the air)
OTA image and installation: https://developers.google.com/android/ota
There has an online flash tool for factory image: https://developers.google.com/android/images