Installing a custom recovery on the HTC One M8 smartphone is going to wipe the stock recovery and replace it with a new one that can do all the same things as the original version and then some. Most of the additional features available from a custom recovery are to help developers and people wanting to flash files. These files are often new ROMs, kernels, rooting files and so forth.
- You must unlock the bootloader on the HTC One M8 smartphone by visiting the HTCDev.com website if you have not done so already. You cannot install a custom recovery on this smartphone without the bootloader unlocked first.
- You need to have a computer that is running on a version of the Windows operating system to use this guide because the ADB available in our guides is the version that works on Windows. There are other versions of ADB out there for Mac and Linux but not only do you need to download the different files to set them up but you also need to follow a different set of instructions. Still, if you do use any of the other versions of ADB and you know what your commands are, you can use the TWRP file that is available in this guide to flash the custom recovery on your HTC One M8 smartphone from the Mac or Linux operating system instead.
BEFORE WE BEGIN
- You need to unlock the Developer Options menu and then enable the USB Debugging Mode  before you connect the HTC One M8 smartphone to the computer with the USB cable if you have not done that already. Sometimes, people, have it locked and sometimes it is already unlocked for people.
HOW TO INSTALL TWRP RECOVERY ON HTC ONE M8
- Download the TWRP Recovery  for the HTC One M8 smartphone directly on the computer.
- Set up the ADB for Windows  on the computer and then come back and continue with this guide when you are done.
- Download and install the ADB Drivers on the computer.
- Open the Downloads folder to find the TWRP file and extract the TWRP Recovery file  in the Downloads folder.
- Shift all of the contents that came out of the TWRP extracted file to the ADB folder, so you have it all in the one directory.
- From inside the ADB and TWRP folder, hold the Shift key down and right-click the white background of the folder and a new menu pops up on the display
- Choose to open a new command window here from the menu.
- Type the first command: “adb reboot bootloader” to get the HTC One M8 smartphone into the bootloader mode.
- Enter the second command: “fastboot flash recovery twrp.img” to get the custom recovery flashed on the M8 smartphone.
- Type the command: “fastboot reboot” and when the M8 smartphone reboots, hold down the hardware button combination to make it first-time boot into the recovery mode.
In conclusion, that is how to install Team Win’s TWRP Recovery on HTC One M8 smartphones by using ADB and a computer. By first-time booting into the recovery mode, we are booting the custom recovery before getting into the Android OS, and that stops the stock recovery from wiping over the custom recovery. You can now reboot back into the normal mode or continue to use the recovery mode. You might also be interested in checking out how to root the HTC One M8 smartphone when it is running on the Android 6.0 Marshmallow software updates.