More details if it can help other people who cannot boot after ubuntu kernel update :
Problem : 1 - I updated natty ubuntu with Update manager. This upgraded kernel from 2.6.38.8 to 2.6.38.10. I noticed some changes on grub but didn't pay attention to the fact that it in fact replaced grub-efi by grub-pc automatically. 2 - During reboot grub failed and i got the dreaded error message error: invalid arch independent ELF magic. grub rescue> After some unsuccessful tries to restore grub from a LiveCD I did the following wich worked : 1 - Changed the boot order in BIOS to boot without using EFI. On my system (Asus SandyBridge H67) this meant selecting the hard drive name boot device instead of the boot device labelled "ubuntu" (EFI) 2 - Boot OK to ubuntu 3 - In Synaptic installed grub-efi (which automatically uninstalled grub-pc) Now i am looking for a way to disable grub changes each time the kernel changes. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/721544 Title: Update replaced grub-efi with grub-pc causing boot failure. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/721544/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs