Help needed, installing stock firmware on a LG / Google Nexus 5X (bullhead)”

@Catrine I think that it would be OK to experiment as we were doing last night but in light of

and

I did a bit more research … perhaps for our next endeavour (??) … I introduce

Hypothetical department

If considering an early version of platform tools maybe required around a date during Nexus development of Oreo (??)

These bullhead downloads have been inspected

Aug 25 2016 bullhead-mtc20k				# leading m Marshmallow		No "if" clause
Sep 27 2016 bullhead-nbd90w				# leading n Nougat			No "if" clause
Aug 18 2017 bullhead-opr6.170623.013	# leading o Oreo			No "if" clause
Nov 21 2018 bullhead-opm7.181205.001	# leading o Oreo			"if" clause is seen

Possible contemporaneous platform-tools to experiment with

For reliable links to specific platform-tools releases please try GitHub - awake558/adb-win: adb.exe fastboot.exe

28.0.0 (June 2018) This revision concentrated on Pie

27.0.1 (December 2017)

27.0.0 (December 2017)

26.0.2 (October 2017) Add fastboot support for Pixel 2 devices.

26.0.1 (September 2017)

26.0.0 (June 2017) Updated with the release of Android Oreo final SDK (API level 26).