1

I have Ubuntu installed in an external device (GPT) in Legacy mode. I could run this Ubuntu in my old Windows 7 laptop. Now I have changed to a Windows 10 laptop in UEFI mode and I can't run ubuntu unless I enable Legacy mode.

So my problem is that I want to change Ubuntu to UEFI mode without reinstalling. When I run Boot-Repair, a message pops up saying:

The current session is in Legacy mode. Please reboot the computer, and use this software in an EFI session.

But I can't open Ubuntu if the legacy mode is disabled!

Is there any solution?

Edit: Solution

  1. Create a EFI partition
  2. As Melebius pointed out, Install Boot-repair in a flash usb
  3. Boot the flash usb in UEFI mode and follow the instructions.
  • Do you run Boot-Repair using a live medium or from your main Ubuntu installation? – Melebius Aug 20 '18 at 9:11
  • From main Installation. I have tried also from a second ubuntu installation (not live session) as posted in this question: askubuntu.com/questions/1067056/… – lsmor Aug 20 '18 at 11:58
  • UEFI's default is gpt partitioning. Did you use gpt on external drive. Most legacy installs are BIOS/MBR. You can convert drive in place from MBR to gpt but may be able to boot using MBR with UEFI. But will need an ESP - efi system partition. Not sure how to create with MBR but it must be FAT32 with boot flag. rodsbooks.com/gdisk/mbr2gpt.html But external drives only boot from /EFI/Boot/bootx64.efi. I typically copy /EFI/ubuntu twice to external and second copy is to /EFI/Boot and then I rename shimx64.efi to bootx64.efi. – oldfred Aug 20 '18 at 14:52
0

As the error message says, you should run Boot-Repair in UEFI mode. Since your main installation does not support that, you have to get a system where it’s possible. Moreover, modifying important properties of the running installations (like moving the root partition) is mostly not possible.

The easiest way is to run Boot-Repair from Ubuntu live medium or even using the Boot-Repair-Disk. Make sure to boot it in UEFI mode, the particular procedure depends on your hardware (or firmware to be precise).

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.