Question

1

Dual-boot Ubuntu and Windows 8 (only boots from "Windows Boot UEFI Recovery")

rated 0 times [ 1] [ 0] / answers: 1 / hits: 1228 / 2 Years ago, tue, february 1, 2022, 8:27:40

Yesterday I was finally able to install ubuntu 12.04.3 (64 bits) on my pre-installed Windows 8 (64 bits) Lenovo Ideapad Z500 (if that is of any help).
I'll just explain the problem that I have now and if you need more info just ask me (such as the steps I followed to install Ubuntu, etc.)
So I boot the computer (UEFI Bios, SecureBoot Disabled, Fast startup on Windows 8 disabled) and GRUB appears correctly (I already ran BootRepair to achieve this), then if I choose Ubuntu, it loads correctly. The problem is when I choose Windows 8 I receive this error:

unknow command `drivemap'

invalid EFI file path

Furthermore, in GRUB I see 2 Ubuntu Boot options alongside many windows options and I just discovered that clicking one: "Windows Boot UEFI Recovery" actually boots my Windows 8 as usual. So, I actually have a working dual boot, but instead of choosing "Windows 8 (loader)" which doesn't boot Windows 8 (and just shows the drivemap error) I have to select the mentioned "Windows Boot UEFI Recovery" option to correctly boot windows 8.
Is there any way to solve this issue??
Thanks in advance!!

Cheers,
Alejandro.

P.S.: The BootInfo generated by BootRepair can be found here http://paste.ubuntu.com/6294680

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answered 2 Years ago luringdge · Accepted Answer

You originally installed Ubuntu in BIOS mode, since you have grub in the protective MBR.
But Boot-Repair converted your install to UEFI by uninstalling grub-pc for BIOS and installed grub-efi for UEFI.

Boot-Repair also added boot entries for Windows in 25_custom and you and manually edit those if the titles are not correct. It had to add new entries as grub has a bug and only creates BIOS boot entries even for UEFI systems. New 13.10 has a fixed grub2 os-prober that does it correctly.

gksudo gedit /etc/grub.d/25_custom

Boot-Repair also did the Windows filename rename. Rod Smith calls it a hack, I consider it a work around for buggy BIOS, but think Boot-Repair may be running it when not required. But we do not know if your UEFI would alllow booting of Ubuntu from UEFI.
The rename is for those UEFI that only boot Windows. So it renames grub2's shim file that has the Microsoft signing key to the Windows file name and you boot the Windows efi file from grub menu that has bkp at beginning of name.

If your want to undo rename. But if then you cannot boot you may have to add the rename again. May be best to have full backup of efi partition.

To undo & to rename files to their original names, you just need to tick the "Restore EFI backups" option of Boot-Repair.