Question: MacBook pro grey screen loop
I updated my MacBook Pro 8,2 today to High Sierra.
It updated successfully then about an hour after the laptop crashed. Upon restarting it displayed the apple logo then a grey screen the reboots and loops doing the same.
So far i've tried:
PRAM reset. cmd+alt+p+r (three times)
SMU reset. shift+ctrl+alt
Hard Drive First Aid in my other mac.
Verbose boot completes then back to grey screen and loop.
single user mode boots then run (fsck -fa) shows as hard drive OK.
Also does the same when booting into recovery(cmd+r) and internet recovery(cmd+alt+r) also same from usb installer.
I'm at a complete loss. Could anyone help please??
MacBook Pro, macOS High Sierra (10.13.1)