LL4 - boot failure following switch from Intel to nVidia card (390 driver)

[m654321]

You have been warned already about using proprietary drivers. I hope someone here can help but it has nothing to do with LL

Thanks kpanic for your reply.
Yes it's an nVidia problem not an OS one, as emphasized in post #1.

I checked the LL Help Manual, but found no "warning" about the nVidia 390 driver under the Graphics Drivers section. 
Maybe I was looking in the wrong section. The only reference I could find on this forum, regarding such a warning, was English Bob's tutorial, discussed above.
When Jerry replied to EB's tutorial, he didn't highlight EB's take-home message about the nVidia driver - this issue
was just one of several points that EB addressed.

I'm surprised that I seem to be the only one reporting this problem, as there must be several LL users out there
with an nVidia Optimus PC - maybe all those concerned just followed EB's tutorial (?) but the caveat was that
that I found switching back to the Intel card problematic, as I highlighted in EB's thread.

Maybe I should have posted this message in the 'Discussion' section rather than in the 'Help' section ...