Hello XDA. I have spent the past couple of weeks struggling with unlocking and rooting this awesome device. After some researching I have decided to put this guide together after stumbling on a lot of fake guides on Google that don't work for the Honor 8x. I hope this helps you!
Step 1: Purchase a bootloader code.
Step 2: Download ADB.
Step 3: Setup your phone
Go to Settings > System > About Phone, and tap "Build Number" 7 times to unlock Developer mode. Go back to System, and tap Developer Options. Enable OEM Unlock and USB Debugging.
Step 4: Unlocking your device
Connect your phone to your PC via USB. Make sure you select "Transfer files" when the message pops up on your phone, and select Trust this computer when the debugging warning pops up. Open your ADB folder, hold Shift and right-click, then select "Open Powershell window" or "Open command prompt". In the next window, type "adb devices" and make sure your device is listed (If not, check to make sure USB debugging is enabled, or reconnect the USB cable.)
After that, type "adb reboot bootloader". Once that is done, type "fastboot oem unlock xxx" (replace xxx with the unique code you purchased in Step 1). Warning! This will format your phone and return it to stock configuration. Your phone now has an unlocked bootloader!
Step 5: Install Magisk Manager.
Step 6: Flashing twrp and Magisk
Download this twrp image:
https://www.filehosting.org/file/details/764535/twrp-kirin.img and place it into your ADB folder.
Then download this magisk ZIP:
https://github.com/topjohnwu/Magisk/releases/download/v17.1/Magisk-v17.1.zip and place it on a spare Micro SD card, and put that card in the device.
Reconnect your device to the PC, again open a Powershell/Command Prompt (as in Step 4).
Type "adb reboot bootloader", then type "fastboot flash recovery_ramdisk twrp-kirin.img". This should complete successfully. Turn off your device by holding down the power button.
Disconnect the phone from USB (do not skip this part otherwise you are unable to boot into recovery). Then hold "Volume UP" and "Power" until the blue Honor logo shows up. Release both buttons. You should see a Teamwin logo and twrp will load.
This version of twrp is a work in progress so the touchscreen does not work (this is currently being worked on by the folks at twrp builder
https://twrpbuilder.github.io/. As soon as they fix it, I will update this guide!). A temporary fix is by using an OTG Cable
https://images-na.ssl-images-amazon.com/images/I/51HI4XhstKL._SX425_.jpg and a standard USB mouse. Use it to swipe-right and select "Install". You might need to "Select storage" and choose your SD card. Find the Magisk zip and install it, then reboot.
Your Honor 8x phone is now rooted!
If this guide was helpful, please consider donating! Bitcoin: 1FPzDYUrQmQMrHbv2ZeAEe883KVNZ8zPV4
Thanks.