WARNING: Everything you do is at your own risk. I am not responsible for any damage to your device resulting from following these instructions.
Unlocking your bootloader is necessary to be able to install custom software on your phone. However, unlocking the bootloader will permanently disable KNOX features on your phone (eFuse memory cannot be reset!), and will probably void your warranty.
A phone with an unlocked bootloader shows two warning messages and you need to press the power button on every boot to acknowledge the warning and proceed with boot.
You can relock the bootloader if you flash the original software through ODIN, but your warranty will still be void and KNOX will still be disabled.
Do not relock the bootloader with flashed custom software, as that can and usually will lead to your phone being permanently destroyed, unable to be flashed, unlocked or powered on successfully. In that case, only a motherboard replacement can help, and since your warranty is void you will have to pay for it!
Your phone’s data will be permanently erased after the bootloader is unlocked, and this cannot be prevented. Do not try to prevent the erase process by shutting off the phone, as that will just corrupt the system and make it difficult to restore the phone to working condition.
- Samsung Android phone running OneUI or Samsung Experience (may work on older TouchWiz phones)
- Phone battery as at least 50% charged
- PC and USB cable
Step 1. Enable Developer options
Open Settings, then About phone. Tap “Build number” a few times (at least 10) until you get a message on screen that “You are now a developer” or that developer mode has been enabled.
Step 2. Enable OEM Unlocking
Go back to Settings, open Developer Options, and tap on OEM unlocking to enable it. A dialog will show asking if you want to Allow OEM unlocking, press Enable.
Step 3. Boot into bootloader menu
Turn the phone off, by holding the power button until a Power Off or Turn Off button appears on screen. Do not press Reboot!
When the phone is off, hold the Volume up, Volume down and Power buttons for a few seconds.
A screen with a warning message will appear.
Step 4. Unlock bootloader
Hold (not press!) Volume up button until the text on the display changes.
Then, press (not hold!) Volume up to indicate that you wish to unlock the bootloader.
The phone will reboot into Recovery mode and perform mandatory data erase.
Step 5. Done
Your phone’s bootloader is now unlocked. You can verify that because when the phone turns on it will show a Warning message indicating that the phone’s bootloader is unlocked and that the “phone can’t be trusted”.
Step 6. Relock bootloader
If you wish to relock the bootloader, perform Steps 1, 2, 3 and step 4. Step 4 will have different text, but the method is the same.
Hold Volume up to indicate you want to relock the bootloader, then press Volume up to agree.
The phone will reboot and wipe data again, and the Warning screen on boot will no longer show, indicating that your device is “secure” and the bootloader is locked.