Bypass a Forgotten Android PIN with ADB (No Root)

Why the PIN Can Be Cleared with ADB

Android stores the lock‑screen PIN in a protected system database that is only accessible to privileged processes. When USB debugging is enabled, the adb daemon runs with the same privileges as the system UI, allowing it to invoke the locksettings service. The command adb shell locksettings clear --old <old‑pin> tells the service to forget the stored PIN, effectively resetting the lock screen.

This works only if the device already trusts the computer (the RSA key is authorized) and the user has previously enabled developer options. If those conditions are not met, the method cannot be used – the device will remain locked and a factory reset may be the only option.

Before You Start

• USB debugging must be enabled on the locked device (Settings ▶ Developer options ▶ USB debugging).
• The computer you will use must be already authorized on the phone. If you never connected the phone to this PC before, the method will not work.
• Install the latest Android Platform‑Tools (ADB) on your PC or Mac.
• Charge the phone to at least 50 % to avoid accidental shutdown during the process.
• Back up any data you can still access (e.g., SD card, cloud services) before proceeding.

Step‑by‑Step Procedure

adb devices

List of devices attached
1234567890abcdef    device

adb shell locksettings clear --old <old‑pin>

adb reboot

Alternative Path: Using Fastboot When USB Debugging Is Not Enabled

If USB debugging was never turned on, the ADB method cannot be used. In that case you can try the fastboot erase userdata command, but be aware it will erase all user data on the device.

1. Power off the phone.
2. Boot into fastboot mode (usually Power + Volume Down).
3. Connect to PC and run fastboot erase userdata.
4. Reboot with fastboot reboot.

This method is a last resort when the device is completely inaccessible.

Troubleshooting Common Issues

• ADB reports "device unauthorized"
  • Disconnect and reconnect the cable.
  • On the phone, look for the RSA‑key prompt and tap Allow. If the prompt never appears, the device’s USB debugging setting may have been disabled by the lock screen – you cannot proceed.
• Command returns "SecurityException"
  • This means the ADB shell does not have the required permission. Verify that the device is running Android 7.0 or newer (the locksettings service was hardened in later releases).
  • On some OEM skins (e.g., Samsung One UI), the command is adb shell locksettings clear --old <old‑pin> --user 0.
• Phone restarts but still asks for PIN
  • Make sure you entered the exact PIN. A typo will cause the command to fail silently.
  • Some devices store the PIN in the hardware‑backed keystore; on those models the ADB method is blocked. In that case, only a factory reset will work.

When This Method Won’t Work

The ADB PIN‑clear relies on two conditions:

1. The device trusts the computer (RSA key authorized).
2. USB debugging is still enabled in the system settings.

If either condition is missing, Android treats the device as a security‑critical environment and refuses the locksettings call. Newer Android versions (10+ on many OEMs) also add a "device‑policy‑manager" check that blocks the command when the device is managed by a corporate profile.

Best Practices to Avoid Future Lock‑outs

• Write down your PIN in a secure password manager.
• Enable Smart Lock (trusted places, devices, or face) as a fallback.
• Periodically verify that USB debugging is still enabled if you rely on ADB for recovery.
• Consider setting a secondary unlock method (pattern, password) that you find easier to remember.

Wrap‑Up

By following the steps above you can safely clear a forgotten Android PIN using ADB, provided the device already trusts your computer and has USB debugging enabled. This approach avoids a full factory reset, preserving your apps and data while restoring access to the device. Always keep a backup of your PIN or enable alternative unlock methods to prevent future lock‑outs.