I may have solved the puzzle but I am not able to explain why the
server was hanging in "firmware init" several times for 30 min.
To have normal "boot time" I did disable
LifecycleController.LCAttributes.CollectSystemInventoryOnRestart
Then I enabled it again and gave the server a reboot.
To my second surprise the server was online after "normal time".
But the other three R320 I got two weeks ago is still stuck in
"firmware init" for 30 min. Perhaps the disable/enable
"LifecycleController.LCAttributes.CollectSystemInventoryOnRestart"
is the key to solve my problems ?