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after installed Ubuntu 16.04 to external drive on Windows 8 system, i can't boot without external drive. if i plug in the Ubuntu 16.04 external drive, i can boot with grub normally. if not, it go to GNU GRUB version 2.02~beta2-36ubuntu prompt. my window use UEFI. i try running "sudo update-grub /dev/sda"( sda is my internal hard drive) but it not work.

this it how i installed Ubuntu 16.04 to external drive and all step i try to fix it.

  1. i format my external drive as ntfs.
  2. i use LiveCD and boot on disk.
  3. i select try Ubuntu.
  4. i partition using gparted by unmount than set
    / 30 GB
    /Swap 8 GB
    /home the rest
  5. i installed Ubuntu 16.04 and i set boot loader at /dev/sda
  6. after i done i can't boot without my LiveCD
  7. so i boot Ubuntu, on Ubuntu, i remove my LiveCD.
  8. now i use boot repair.
  9. it working without my LiveCD but i still need my external drive to be plug in.
  10. so i try running "sudo update-grub /dev/sda" but still not working.
  11. i use boot repair again and here is the log https://paste2.org/YjdhLnDd

thank i new any os other than window.
Edit: My external drive is wd element se 500gb with usb2.0

update i found out that some part of grub to is in /dev/sda2 and i don't know how to move it to sdb

i move grub2 to sdb1 now using http://howtoubuntu.org/how-to-repair-restore-reinstall-grub-2-with-a-ubuntu-live-cd but now no grub when boot but i can't boot to grub2

khunjuice
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1 Answers1

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The problem that you're having comes from booting into Legacy mode and trying to install grub into Drive /dev/sda during your install. You could install grub to /dev/sdb and set your BIOS for /dev/sdb as your boot priority. During that will boot you to Ubuntu. However, you won't have boot options to boot to Windows.

While there may be a number of methods around this, the simplest method would be to install an Ubuntu partition on /dev/sda. This can be a very small installation, just enough to have the basic install which can be as small as 8 gigs.

When you boot to the UEFI version of Ubuntu on /dev/sda and run update-grub if your external drive is installed it along with any other OSes detected will be added to the boot menu.

Now when you select UEFI Ubuntu from as your BIOS boot option, you'll have all the Operating systems included all the external drives in the Grub menu. You'll be able to select either one for your default, including Windows.

The information is automatically added to the EFI partition on /dev/sda.

There are many "seemingly" complex descriptions for how to manually edit the EFI partition to do this. But I consider spending 8 gigs of space to allow the Ubuntu install to do this automatically well spent for the ease. Anytime you want to make a change, just boot to the Ubuntu on the /dev/sda drive and run update-grub to have any changes to be automatically reconfigured.

The steps above are to provide being able to have Windows included in your Boot menu.

If you don't care to have your UEFI Windows installation included in your boot menu. Just install group on /dev/sdb (your external drive). Set your BIOS for legacy with /dev/sdb as your default boot device.

L. D. James
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