How to restore android_id on Android Pie 9.0 and Oreo 8.0

This thread above can be REALLY helpful.

[APP] Device ID Changer for Oreo (16/Apr)(v0.9.3-stable)

A simple and elegant App that help you monitor Android IDs on Oreo devices.

https://forum.xda-developers.com/android/general/app-device-id-changer-oreo-13-aprv0-9-2-t3777299

How to change Android ID on Oreo with ROOT

In Oreo and Pie, Android ID (Settings.Secure.ANDROID_ID or SSAID) has a different value for each application and each user on the device.

You can find xml file with IDs in:

/data/system/users/0/*

The best way is to backup the hole folder /data/system/users/0/* and restore on the new phone (should be done in TWRP or something similar)

This folder /data/system/users/0/registered_services was also backed up and restored.

Forget how things were done before with some queries like...

adb shell content query --uri content://settings/secure --where "name=\'android_id\'" 

/data/system/users/0/settings_ssaid.xmlAnd it looks like:

In order to change the ID for an application you need to follow a few simple steps: 
1. Make sure that you have ROOT on your device
2. Open file “/data/system/users/0/settings_ssaid.xml” with any editor that supports ROOT
3. Change “value” and “defaultValue” to new Android ID.
4. Save the file
5. Reboot your device to apply changes