These are my YouTube Video tutorials for unlocking and rooting the Firestick 4K.
Unlock and Root a Firestick 4K – Part 1
This is part 1 (of a 3-part series) and shows how to take the 4K apart and short the pins of the capacitor.
Unlock and Root a Firestick 4K – Part 2
This is part 2 and it assumes you have already followed part 1 and have prepared the 4K to be bootloader unlocked (by removing the 4K casing and shorting the capacitor with some tin foil).
In this part 2 we will run the exploit to unlock the bootloader (in a customised Linux installation), root the 4K and disable Amazon OTA updates.
Unlock and Root a Firestick 4K – Part 3
This is part 3 and it assumes you have already followed parts 1 and 2 and have already rooted your Firestick 4K.
In this part 3 we will completely remove the Amazon Launcher (home screens).
There are also a couple of useful apps (a File Explorer and a replacement onscreen keyboard).
Finally, for fun there is a weather forecast app.
Unlock and Root a Firestick 4K – Create a Virtual Machine
This is an addition to my 3-part series on how to unlock the Firestick 4K bootloader, install TWRP and root the Firestick 4K.
This additional video shows how to use a virtual machine, instead of a bootable USB stick to run the exploit code.
The processes for running the exploit, rooting and all the other fixes are identical in the VM to when using a USB stick.
As it states in the video, the use of a virtual machine is unsupported by the good folks of xda.
However I have used it with no issues on every firestick I have unlocked.