Comment 14 for bug 1890415

I came across this bug looking for a solution.

I can reproduce on 1.75 and now 1.76, W variant of the BIOS on my X390 Yoga i5 no vpro.

When you shutdown/reboot the laptop, everything shuts down like normal, but my FnLock and Mute keys stay lit and the screen is black no backlight. The computer wont power back on unless I disconnect any USB-C power sources then Ctrl-Alt-Delete or hold the power button down until it resets.

USB-C video/network dongles don't seem to affect it, nor does thunderbolt. Only power adapters cause it to hang. I tried both USB-C ports with my power adapter and they both do it.

I experience this on any Linux distro I try. From kernels 5.4 to 5.8, haven't tried further back.

For me the 1.76 release wasn't showing up in fwupdmgr so I manually installed it.

Simply download n2lul15w.zip from https://pcsupport.lenovo.com/sk/en/products/laptops-and-netbooks/thinkpad-x-series-laptops/thinkpad-x390-yoga/downloads/DS539544 and unzip it.

Install the W variant with

$ sudo fwupdmgr install ./N2LET76W.cab

or the P variant (absolute persistence module must be disabled in the BIOS)

Install the W variant with

$ sudo fwupdmgr install ./N2LET76P.cab

The P or W is if you want the Absolute Persistence module to be force disabled (P).