Anybody got a hold of a working twrp image for FP2? If there is, toggle OEM Unlocking on Developer options and make sure to have USB debugging enabled as well.
Another thing that you'll need would be adb/fastboot files (google minimal adb and fastboot, get it from xda too) along with the correct drivers for your FP2.
adb reboot fastboot, if the phone didn't reboot to fastboot then you'll need Power+Volumn Up when powering the phone on and select fastboot, verify the connection via
fastboot devices then do a
fastboot boot recovery twrp.img (the twrp.img should be placed on the same folder of the adb/fastboot) and that should have your FP2 a temp access to twrp to flash SuperSU for rooting. If you want to keep twrp then run
fastboot oem unlock followed by
fastboot oem unlock confirm as well as
fastboot flashing unlock then afterwards
fastboot flash recovery twrp.img
Just dropping by as I got curious to this thread, I don't have FP2 though so these are trivial codes