The HTC One M8 comes with locked bootloader, you can see it on the bootloader mode (turn off the phone, then press and hold Vol down + Power), it should say *** LOCKED *** at the top. However, this status will change to UNLOCKED along with tampered once you unlock the bootloader via HTCDev or gain S-OFF with Firewater. We believe this is one of the efforts made by HTC to reduce the interest of users to unlock their smartphones. Furthermore, most likely your device will be rejected when you claim the warranty.
Fortunately, there is a developer from xda – scotty1223 – who expose a method to reset the HTC One M8 bootloader from UNLOCKED to LOCKED again with simple adb command line. The best thing is, to get this done, we don’t need a token from the HTCDev or submitting our phone’s personal information to HTC. According to the dev, this method should work on several variants, including Verizon, Sprint, AT&T, T-Mobile, etc.
Actually, there is an easy command to lock the bootloader after you unlock it, simply by running “fastboot oem lock” command, sadly this command has a small success rate, and has a possibility to fail. In addition, this command will only change the UNLOCKED status to RELOCKED not LOCKED.
- HTC One M8, S-OFF’ed with Firewater.
- Get the updated HTC USB drivers, without HTC Sync.
- A Windows, Mac or Linux computer. However, this guide made for Windows PC.
- Setup adb on your computer.
- Enable USB debugging
Reset the HTC One M8 UNLOCKED status to LOCKED
- Get into a folder where you save the adb files.
- From there, hold shift and hit mouse right-click then choose “Open command window here” option.
- Perform the following command to check if adb has worked well:
It should show your phone serial number.
- Here is the command line you should run, one at a time, re-type, do not copy paste:
echo -ne ‘\x00\x00\x00\x00’ | dd of=/dev/block/mmcblk0p2 bs=1 seek=33796
- Now verify that your HTC One M8 status has changed to LOCKED, boot into bootloader mode:
adb reboot bootloader