How to Lock the Bootloader on a Samsung Galaxy A21s: Step-by-Step Guide
HardReset.InfoNovember 25, 20255 min96 views
1 connections·2 entities in this video→Preparing to Lock the Bootloader
- 💡 Backup your data before starting, as locking the bootloader will erase all data on your phone.
- 🔑 Navigate to Settings > About phone > Software information and tap the Build number seven times to enable Developer Options.
- ⚙️ Within Developer Options, verify that OEM Unlocking is enabled and indicates that the bootloader is already unlocked.
Locking the Bootloader
- 🔌 Power off the phone and unplug any connected USB cable.
- 💻 Connect the USB cable to your computer, but not yet to the phone.
- ⬆️⬇️ Simultaneously press and hold the Volume Up and Volume Down buttons, then plug the USB cable into the phone.
- ⬆️ Press and hold Volume Up to enter the bootloader menu.
- ✅ Confirm the bootloader lock by pressing Volume Up when prompted.
Post-Lock Setup and Verification
- ⏳ The phone will erase data and relock the bootloader, which may take up to 5 minutes.
- 🚀 During the initial setup, it's recommended to skip Wi-Fi connection to expedite the process.
- ⚙️ After setup, reconnect to Wi-Fi, then navigate back to Developer Options.
- 🔒 Disable OEM Unlocking within Developer Options and restart the phone to complete the process.
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Samsung Galaxy A21sLock BootloaderUnlock BootloaderOEM UnlockingDeveloper OptionsSoftware InformationBuild NumberData BackupAndroid SecurityPhone Setup
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