I have a macbook Pro mid 2009, with three partitions : OSX 10.8.5, Ubuntu 13.04 and Windows 7. EFI and GRUB are here, first EFI boots with offering the choice of the three systems then, if Linux or Windows is chosen, GRUB shows up.
Everything worked fine until I cleared NVRAM by pressing the cmd+P+R combination while booting on OSX.
Now, Linux boots correctly but just before showing me the login screen, Linux shows me a blank screen with a corsor blinking at me, I can write things but execute nothing.
How to fix it?
I can furnish more precision if you tell me what command line to execute.