I have managed somehow to mess up my grub (on start-up, I only get a black screen with the message "Reboot and select proper boot devices"), after the making of some bootable usb stick had gone wrong. When I try using Boot repair (in a live Ubuntu session), I get the message:
"The boot of your PC is in EFI mode, but no EFI partition was detected. You may want to retry after creating a EFI partition (FAT32, 100MB~250MB, start of the disk, boot flag).
Do you want to continue?"
(of course, if I do continue, it eventually tells me that all has been repaired, but on reboot I still have the same problem as before, the grub not working).
I got this message (about EFI, from Boot repair) after I had added a FAT32 (148 MB, boot flag) on sda1 and an unformated (2 MB, bios_grub flag) on sda2.
I have Ubuntu 12.10. There is no EFI formatting option in GParted.
Any advice on what I should do is greatly appreciated!
Thanks in advance,