How to Lock the Bootloader on a Samsung Galaxy A71

Preparing to Lock the Bootloader

• ⚠️ Locking the bootloader on your Samsung Galaxy A71 will trigger a factory reset, erasing all user data. Ensure you back up photos, messages, and apps beforehand.
• 📶 Connect your device to a Wi-Fi network to proceed with the setup and subsequent steps.

Enabling Developer Options and Checking OEM Unlocking

• 📱 Navigate to Settings > About phone > Software information and tap the build number repeatedly until developer mode is enabled.
• ⚙️ Access Developer Options and observe the status of the OEM unlocking feature, which will initially be enabled but unavailable for direct modification.

The Bootloader Locking Process

• 🔌 Power off your device. You will need a working USB-C cable connected to a PC.
• 🎛️ Simultaneously hold both volume keys and then insert the USB-C cable while continuing to hold the volume keys.
• ⬆️ After the device prompts, press the volume up button to confirm the bootloader lock and initiate the factory reset.
• ⏳ The phone will restart and perform a factory reset; unplug the cable once the reset begins and wait for the device to power on.

Post-Reset Setup and Finalization

• ✅ Complete the initial device setup process, skipping unnecessary steps.
• 📶 Reconnect to Wi-Fi and re-enable Developer Options by tapping the build number again.
• 🔒 In Developer Options, disable the OEM unlocking feature.
• 🔄 Finally, restart your phone to fully lock the bootloader and enable device protection features.