I recently installed Ubuntu 15.10 on an HP Z-Book running Windows 8.1.

I installed grub on an sda partition mounted for /boot. Is there some way that I can boot on that partition and possibly use grub to select either windows 8 or ubuntu linux?

Currently, when booting my pc with OS selector, it goes straight into windows 8 (with secure and fast boot both turned off on UEFI hybrid boot mode).

  • Usually best not to have separate /boot. And /boot is not the ESP - efi system partition. Sony, HP & others: askubuntu.com/questions/486752/… Rename bootx64.efi askubuntu.com/questions/597052/…
    – oldfred
    Jan 24, 2016 at 21:31
  • @oldfred Tried copying grub file according to instructions in the links. Unfortunately the file had r/w problems, probably due to a fatal error explained here. I tried to install grub like in the linked page but being a linux noob, I managed to mess up my windows boot (thought that mounted sda is just copy and I deleted some files). Right now I deleted my hard (no tears shed for windows 8). Have to research how to set grub to load when pc boots now and not manualy select efi.
    – wraithie
    Jan 25, 2016 at 15:01
  • @oldfred If you believe you can answer the above question, please do. As explained in my comment I'm not focusing on it anymore. At least you can provide some info that might help a possible searcher.
    – wraithie
    Jan 25, 2016 at 15:02
  • Sometimes the FAT32 partition gets corrupted and needs either a chkdsk from Windows or fsck from Linux. Must be unmounted, change sdb1 in example to your FAT32 partition: sudo dosfsck -t -a -w /dev/sdb1 The -a seems to help in clearing dirty bit bbs.archlinux.org/viewtopic.php?id=164185
    – oldfred
    Jan 25, 2016 at 19:29
  • @oldfred Can't do that anymore I'm afraid, the fat32 partition changed completely as result of disk wipe. I posted the question regarding my current situation here. Like I said above, if you can, answer this question. You could perhaps develop on your first comment and explain why /boot on seperate partition is a bad idea. If renaming grubx64.efi in bootx62.efi is a general solution then I think you should mention it. Would help solve both questions.
    – wraithie
    Jan 25, 2016 at 23:05

1 Answer 1


As mentioned by @oldfred in the comments, making a backup of original windows bootx64.efi and copying grubx64.efi should do the trick.

An even better solution for me was running ubuntu boot repair, recommended repair. It made a dir /boot/efi/EFI/Windows/Boot/ with grub already named as bootx64.efi. Using that, when booting from OS selector, grub loads successfully.

EDIT: If boot repair page returns internal server error, this is how boot repair can be installed:

sudo add-apt-repository -y ppa:yannubuntu/boot-repair
sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair

Boot repair window should show up after install.

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.