There have been some reports of corrupted /EFI/ubuntu directories, so could you confirm that you can see the files in this directory -- either from a legacy boot (where you will have to mount the EFI partition somewhere), or live boot? If the directory is unreadable, uefi boots cannot find the necessary files to continue booting. (bug 1090829)
There have been some reports of corrupted /EFI/ubuntu directories, so could you confirm that you can see the files in this directory -- either from a legacy boot (where you will have to mount the EFI partition somewhere), or live boot? If the directory is unreadable, uefi boots cannot find the necessary files to continue booting. (bug 1090829)