Tutorial To Unlock HTC One M8 Bootloader:
1) Before getting started with the rooting procedure of your HTC smartphone, we have to unlock it. To do so, first go to “Settings -> Power” and make sure that “Fast Boot” is OFF.
2) Next, switch off your device and press Volume Down and Power buttonsimultaneously until you see the bootloader menu. Now, use the power button to select the FASTBOOT mode.
3) Now, connect your device to the computer with the help of Original USB data cable. Once done, download fastboot.zip and extract it contents to a folder in your computer.
4) In the extracted folder, press shift and right-click on an empty space. Once you have done that, you will be able to see the option “Open Command Window here“. Click on it to open the Command prompt there. Once done, enter the following command:
fastboot oem get_identifier_token
5) You will be able to see the Identifier token. Copy and save it to a notepad. Once done, go to HTC dev and select “Unlock Bootloader“. You will be asked to register. Just follow the on-screen instructions to register. Once done, go to http://www.htcdev.com/bootloader/ page, choose HTC One M8 and click the “Begin Unlock Bootloader” button.
6) Just follow the on-screen instructions until you are in the “Step 5“. In that step, you will be asked to enter the identifier token in a box under the title “My Device Identifier Token“. Just copy and paste the identifier token from the notepad (previous step) and proceed. Once you have done that, the HTC dev team will automatically email the unlock key for your device.
7) Now, go to your register email, download “unlock_code.bin” and save it in the FASTBOOT files extracted folder. Once done, go to the Command window again and type the following command:
fastboot flash unlocktoken Unlock_code.bin
8) You will get an unlock token check successful message. Now go to your device and choose “Yes” with the help of power key. Your device will reboot shortly. That’s it. Now you have unlocked the bootloader of your HTC One M8 smartphone.