Manjaro.org recommend Minisforum computer. I researched a little about Minisforum support.
I cannot find any BIOS update support for this kind of computer.
Any one know more about it?
Here is a detailed tutorial (HP BIOS/Firmware updating - Tutorials - Manjaro Linux Forum) specifically addressing this issue. I hope that it will help you.
Lookup the mainboard model:
inxi -M
and go to the vendors website.
Can you try this?