Introduction

Switch to secondary user after boot of a rooted Android 10.

Instructions

To enable the application as Device Owner in order have permissions to change the user:

adb root
adb shell dpm set-device-owner com.example.switchuser/.AppAdminReceiver

User restrictions

Hardening:

1. Dump /data/system/users/10.xml where 10 is the id of the user. The file looks like this:

<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
<user id="10" serialNumber="10" flags="16" created="1598034338552" lastLoggedIn="1598035769294" lastLoggedInFingerprint="Android/sdk_phone_x86_64/generic_x86_64:10/QPP6.190730.005.B1/5775370:userdebug/test-keys" icon="/data/system/users/10/photo.png" profileBadge="0">
    <name>New user</name>
    <restrictions no_sms="true" no_outgoing_calls="true" />
</user>

2. Add more restrictions. The list of restrictions can be founded on UserManager Documentation
3. push the changes

adb push 10.xml /data/system/users/10.xml

Reboot

Once the device start the application switch the user to the secondary user.

Tests

The app was tested on AVD (Android Virtual Device)