Although having an unlocked bootloader is really useful in many ways such as flashing firmware (factory images). Installing TWRP and also getting root, however, can also lead to blocked services on your device. Because of security reasons, and thus you guys might want to relock the bootloader to avail those services as well. In this article, we are going to talk about How to Relock Bootloader Through Fastboot on Android. Let’s begin!
Earlier today, Google released an update to SafetyNet that now also considers a device’s bootloader unlock status to trigger SafetyNet and turn off certain services, such as Android Pay. Thankfully though, relocking the bootloader will solve the issue for you actually. But (of course) you’ll lose all the advantages that come along with having an unlocked bootloader on your device as well.
The fastboot commands in order to relock the bootloader are not the same for all devices. So we’ve also put together a list of all known Fastboot commands that you guys can use in order to relock the bootloader on your device in the instructions below as well. First things first, just make sure you have all the resources listed below to successfully lock the Bootloader on your mobile device as well.
Things you will need
- Latest Stock Recovery and ROM for your device through your OEM.
- Now install ADB and Fastboot set up on your PC.
- Custom Recovery installed on your mobile device as well.
What you guys should keep in mind
Relocking the bootloader can not also be undone on many devices especially phones manufactured via Xiaomi. Most users that have relocked their bootloader upon unlocking were unable to re-unlock it via any available method. Thus make sure that you want to go back in order to stock ROM and would not like to install a Custom ROM anytime in the future as well.
Also, relocking the bootloader will also delete all of your data and files. So make sure to backup your data before proceeding along with this guide.
Note: However, this method works for most Android devices even if they are running OEM skins. There is also a slight chance that additional steps might be required relying on your manufacturer.
This is especially the case along with Chinese manufacturers such as Xiaomi that have unlocking linked to their cloud backup service of Mi Account as well. You should check the XDA page for your device in order to check for any additional steps. That might be required for you before proceeding along with the guide below.
How to Relock Bootloader via Fastboot
- First, download the Stock ROM and Recovery on the local storage of your device.
- Reboot your device into the custom recovery installed on your device and flash the Stock ROM and recovery as well.
Note: Most of the time manufacturers bundle stock recovery along with their latest firmware nowadays. Relying on your manufacturer you might have a single .zip file or two .zip files as well. If you guys have two of them, make sure to install the ROM before the recovery or you guys could brick your device.
- When both utilities are flashed, your device should reboot along with the Stock recovery and ROM installed. Now confirm that the stock recovery is working as intended via rebooting your device when holding the ‘Volume Up’ button.
Note: however, most stock Android phones use the Volume Up button in order to boot into recovery mode. The procedure could be different for your mobile device as well. An instant web search will also help you find the right key combination in order to boot your device into recovery mode.
- When you guys are in recovery mode, you should see your stock recovery options and UI as well. This means that the Recovery was flashed correctly as well. Now reboot your device and boot into the fast boot mode for your device as well.
Fastboot mode can also be accessed via holding down the ‘Volume Down’ button on most devices, however, rebooting. If this does not work for you, an instant web search will also help you identify the right key combination for your device.
- Now that your device has booted into the recovery mode, you then have to connect it to your PC. And open Command Prompt in the ADB directory for your system as well.
- Then type in ‘Fastboot devices’ and also confirm that your device is being recognized via your system.
Now issue the following command in order to relock the bootloader.
fastboot oem lock OR fastboot flashing lock
Note: For devices released in 2015 or later, then you have to use the ‘fastboot flashing lock’ command. Although, the first command given above may also work as well.
- You should now also get a prompt for locking your bootloader on your device as well. You guys have to confirm your selection and then also wait for the process to complete.
Note: Do not disconnect your device during this process and make sure that there are no interruptions during this process. Any glitch or power outage during this process can also brick your device.
- When the process completes, your device’s bootloader should be locked and then you should be running your stock ROM and recovery. You will now also be eligible for OTA updates from your manufacturer as well.
Alright, That was all Folks! I hope you guys like this article and also find it helpful to you. Give us your feedback on it. Also if you guys have further queries and issues related to this article. Then let us know in the comments section below. We will get back to you shortly.
Have a Great Day!