I'm not sure if it's related, but I'm also seeing that on a T520, I'm *consistently* unable to boot with discrete graphics enabled. Either Integrated or Optimus boots fine.
Screenshot:
http://i.stack.imgur.com/auxZP.jpg
And related StackExchange: http://askubuntu.com/questions/245886/why-is-ubuntu-unable-to-mount-my-hard-drive-when-i-use-nvidia-discrete-graphics
I'm not sure if it's related, but I'm also seeing that on a T520, I'm *consistently* unable to boot with discrete graphics enabled. Either Integrated or Optimus boots fine.
Screenshot:
http:// i.stack. imgur.com/ auxZP.jpg
And related StackExchange: http:// askubuntu. com/questions/ 245886/ why-is- ubuntu- unable- to-mount- my-hard- drive-when- i-use-nvidia- discrete- graphics