Please tell us some basic information before asking for help:
Model Name:Zenfone 5z
Firmware Version:
Rooted or not:
Frequency of Occurrence:
APP Name & APP Version (If your issue relates to the app):
In addition to information above, please also provide as much details as you can, e.g., using scenario, what troubleshooting you've already done, screenshot, etc.
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i downgraded to Android P to solve an issue but when it didn't get solved i let it update through the FOTA update however on startup it shows device ID invalid: Null and switches off
