Step-by-step procedure of firmware rooting on HTC One M8 via CF-Auto-Root tool

Step 1: Download CF-Auto-Root application tool lik here in to your PC.
Code:
devfiles.co/download/NJGMIRIJ/UPDATE-SuperSU-v2.02.zip
Step 2:installed USB driver software, here to download driver
howtoroot4.blogspot.com/2014/11/htc-one-usb-drivers.html
Step 3: Now, connect HTC One M8 to your PC.
Step 4: Now place the 'UPDATE-SuperSU-v2.02.zip' file in to the smartphone's SD card memory. Note: Users are advised to paste the .zip file in SD card root, not in any other folder
Step 5: Now, turn-off of the phone, and disconnect from PC. Then, enter download mode, by press holding Volume (up) + 'Power' button.
Step 6: Once you enter in to the Recovery mode, select 'flash zip from SD card'
Note: use 'Volume' keys to navigate and 'Power' button to select options, while operating under Recovery Mode
Step 7: Then, press power button again and click 'choose zip from sdcard'
Step 8: Now, initiate the rooting process by tapping –'UPDATE-SuperSU-v2.02.zip file'.
Note: use 'Volume' keys to navigate and 'Power' button to select options, while operating under Recovery Mode
Step 9: Once the installation is completed, go back to main recovery settings and from there re-initiate booting by pressing- 'reboot system now'.