10.13 update fails

[oli.mathieu]

I have a laptop (Specs in my signature) with multi booting on the internal M.2NVME, with clover
It works fi either with High sierra or W10
But ( because there is a "but :-D) I can't succeed to update High sierra either via the AppStore or with the Combo Update.
It reboots on the "update install volume" in clover as expected. and finally fails and leaves the system untouched.
Any clue ?
I suspect the multi booting is disturbing the process, no ? if so, How ?
Thanks in advance

 

[oli.mathieu]

I cloned internal mac partition on external USB drive
I booted on the external USB drive
I updated MacOS (several reboot)
I cloned back the external USB partition on the internal mas partition.

Any better way ?

 

[Going Bald]

For help with a laptop best to post in the laptop forum