Bootloader unlock process on Galaxy A21s is a very simple process unlike other OEMs which use fastboot to unlock the bootloader. in addition, I will be taking you through a very simple step by step guide which I bet to be a buttery smooth experience even for the first time users.
How to Unlock Bootloader on Galaxy A21s?
- Enable Developer options on your Galaxy A21s, which is hidden.
- Find and enable OEM unlocking.
- Then scroll down a little bit and enable the USB debugging.
- Then boot the phone into Download mode either using adb command or by pressing key combination.
- In the download mode, you will see Volume up long press: Device unlock mode. Press and hold the Volume Up button for few seconds till it enters into bootloader unlock mode.
- Once you are on the Unlock bootloader screen, read the message carefully and press the Volume Up button to unlock the bootloader.
- The phone will restart automatically and will erase all the data.
- If you think the bootloader is unlocked, in fact it might not, yet! Read the below section on how to let VaultKeeper unlock Galaxy A21s’s bootloader permanently.
Allow VaultKeeper to Completely Unlock the Bootloader on Galaxy A21s
VaultKeeper, RMM State: prenormal etc. are not new things. They are at least 2 years old from now.
The VaultKeeper is some kind of “thief” protection service that is running on your Galaxy A21s. The VaultKeeper service may try to lock the bootloader again if the following steps are not done immediately after the bootloader unlock on Galaxy A21s.
To make sure that the VaultKeeper fully unlocks the bootloader to allow foreign partition flashing, which is important if you want to flash TWRP or want to ROOT using Magisk etc. then follow the below instructions.
- Immediately after the bootloader unlock, the phone will be wiped and restarted automatically.
- During the setup, connect the Galaxy A21s to an internet source.
- Enable Developer options again!
- Confirm that the OEM unlocking option exists and greyed out!
There is something called as
VaultKeeper that will try to relock the bootloader after the data wipe.
What to do after unlocking bootloader on Galaxy A21s?
– Install TWRP on your Galaxy A21s
– You can root the Galaxy A21s
– Install custom ROM such LineageOS 17.1 etc.
If you face any problem after following this guide or your are unable to unlock the bootloader on your Galaxy A21s, then login and leave a comment on this thread to get an instant reply from any of the forum users.