I've been iddle some time but I'm coming back with some responses I discovered by researching this a little bit.   1/ In order to have a *full* serial console, you need to uncomment/comment these lines in grub.cfg: set extra_args_3617='earlycon=uart8250,io,0x3f8,115200n8 earlyprintk loglevel=15' #set extra_args_3617='' Then you can observe the complete boot process with a simple "qm terminal <vmid>".   2/ When doing so, I discovered what was happening: [    0