@planner Any reason why, may I ask? It is pretty straightforward using the fastboot command. You need to download a stock ROM and TWRP for OP5T. You need to have ADB and Fastboot drivers installed (I install Android Studio as it has the latest drivers)
Power of the phone and wait a couple of minutes.
Boot into the bootloader by pressing Volume down and the power button together (when it powers on release the power button)
Attach the phone to a PC with a USB cable
Open up a command prompt in the fastboot folder (if using Android studio it is the Platform Tools folder)
Flash TWRP using the command ./fastboot flash recovery <location of the TWRP image>
Once in TWRP go to Wipe and Wipe Data, type in yes
Go back to Wipe and choose advanced and tick the Cache and system and slide the button to wipe them
In the PC file explorer locate the phone and copy the OP5T stock ROM to the root of the device storage (i.e. NOT in a folder)
In TWRP choose install and navigate to the ROM file you copied and install it.
If it fails there are other ways to go back to stock...
Google is your friend use the XDA-developers forum or the oneplus forums as they have other methods.
