Comment # 7 on bug 944978 from Dominique Leuenberger

(In reply to Alberto Zacchetti from comment #6)
> Ok, I found the problem: in runlevel >= 3 is the NetworkManager.service to
> hangs the system. Therefore, when installing, the system hangs due to kms
> (nomodeset solve this), while from the first reboot, the system hangs due to
> NetworkManager.service.

Do you have any logfile supporting the theory that NM is the task hanging?