In order to boot Windows on UEFI systems : WORKAROUND with 'Secure Boot' DISABLED -------------------------------------- The 'grub.cfg' menuentry below, which may conceivably be generated by 'os-prober', works only with 'Secure Boot' disabled :
menuentry "Windows booted from its NTFS partition" { insmod part_msdos # and/or part_gpt, depending on the partition table(s) insmod ntfs set WindowsEFI=/EFI/Microsoft/Boot/bootmgfw.efi if [ x$feature_platform_search_hint = xy ]; then search -n -s --hint-bios=hd0,msdos2 --hint-efi=hd0,msdos2 --hint-baremetal=ahci0,msdos2 -f $WindowsEFI else search -n -s -f $WindowsEFI fi chainloader $WindowsEFI } But with 'Secure Boot' enabled, the above menuentry systematically fails with following error message : Secure boot forbids loading module from (hd0,msdos2)/boot/grub/x86_64-efi/ntfs.mod WORKAROUND with 'Secure Boot' ENABLED ------------------------------------- In order to boot Windows on UEFI with 'Secure Boot' enabled, I have successfully installed following workaround : - Think : On installation of the Linux distribution (Ubuntu or another one) with UEFI, the installer normally creates an 'EFI boot' partition formatted as 'vfat'. - Think : This 'EFI boot' partition is read by 'grub' WITHOUT the need of the insecure 'ntfs.mod', and is precisely dedicated to booting. So, let's use it : - Under Linux, mount the Windows partition, and copy the content of its '/EFI' folder under '/boot/efi/EFI'. For example : sudo cp -p -r /media/user/Windows-Label/EFI/* /boot/efi/EFI/ (you can safely ignore 'cp: failed to preserve ownership' error messages) - Then, replacing 'msdos2' by the partition number of the Windows partition on your system, write following lines at the END of '/etc/grub.d/40_custom' : menuentry "Windows booted from EFI boot partition" { insmod part_msdos # and/or part_gpt, depending on the partition table(s) set WindowsEFI=/EFI/Microsoft/Boot/bootmgfw.efi if [ x$feature_platform_search_hint = xy ]; then search -n -s --hint-bios=hd0,msdos2 --hint-efi=hd0,msdos2 --hint-baremetal=ahci0,msdos2 -f $WindowsEFI else search -n -s -f $WindowsEFI fi chainloader $WindowsEFI } FIXING THE BUG FOR ALL CASES ---------------------------- I suggest that 'os-prober' automatically performs the workaround just above, which involves copying boot files from the Windows partition to the 'EFI boot' partition. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1024383 Title: update-grub generates only BIOS based menu entries for Windows, even on UEFI systems To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1024383/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs