Comment # 12 on bug 1087525 from Takashi Iwai

OK, then let's try something different:
- Remove blacklist again, run mkinitrd to rebuild initrd
- Reboot without nomodeset, but also remove quiet option.
  And add plymouth.enable=0 drm.debug=0x0e boot options, too.

If this makes the system stalled, check whether it's really a crash or it's
just a blank screen.  It'd be best if you can remote-access to this machine. 
If not, maybe try like:
  ctrl-alt-F1
  ctrl-alt-delete
to reboot.  If the machine reacts with the sequence, it means that it's alive.
Then you can see journalctl -b-1 to get the previous log.