On a multi-boot Linux computer where Ubuntu has already been installed, adding on Manjaro Linux installs its own version of Grub (that I’ll call Arch-Grub) that is different but compatible with that previously installed (that I’ll call Debian-Grub).
Addendum: The below instructions worked for Manjaro releases before March 2018. For some instructions dated May 2021 (that worked in February 2022), see “Restore Manjaro boot after dualbooted Ubuntu-Mate replaced grub” at https://forum.manjaro.org/t/restore-manjaro-boot-after-dualbooted-ubuntu-mate-replaced-grub/67583/2
- On some of my laptops, the “grub-install — rechedk — no-rs-codes” would give a response “grub-install: error: install device isn’t specified”.
- The manual command was then “grub-install /dev/sda” for the laptop with a single drive, and “grub-install /dev/sdb” for the laptop with two drives where I wanted to not boot off the first drive with Windows installed.
Updating Ubuntu to a newer version (or installing an older version) restores Debian-Grub, replacing the working Arch-Grub. This will result in Debian-Grub showing both Ubuntu and Manjaro as options on booting. Choosing Ubuntu from Arch-Grub works just fine. However, choosing Manjaro from Debian-Grub will lead to a black screen with messages, e.g.:
… Failed to execute /init (error -13)
… Starting init: /sbin/init exists but couldn’t execute it (error -13)
… Starting init: /bin/init exists but couldn’t execute it (error -13)
… Starting init: /bin/sh exists but couldn’t execute it (error -13)
… Kernel panic – not syncing: No working init found. Try passing init option to kernel …
… —[ end Kernel panic – not syncing: No working init found …
On my Thinkpad X200, the only way to exit this screen was to pull the battery for a cold reboot.
The reason that Arch-Grub is different from Debian-Grub is that it loads Intel microcode before the OS, rather than inside the OS.
Manjaro will load intel-ucode using grub.
Unlike other OS’s, it is not built into initd (initramfs) nor into kernel.
But it will load this separately (first) from /boot/intel-ucode.img
But don’t worry about this. It will be done automatically for you when you install or boot Manjaro (provided you use Manjaro’s bootloader (grub) as default bootloader).
… says gohlip | “Does manjaro supply intel microcode automatically?” | May 2016 at https://forum.manjaro.org/t/does-manjaro-supply-intel-microcode-automatically/646/2
Thus, Arch-Grub does more work than Debian-Grub. Arch-Grub will successfully start Ubuntu (based on Debian), but Debian-Grub will not successfully start Manjaro (based on Arch). The resolution is to replace Debian-Grub with Arch-Grub to the multiboot system.
gohlip suggests seven ways to fix this …
1. chroot from livecd (which you’re aware of, I think)
2. use this method which does not need chroot or boot livecd but still make manjaro default boot
3. remove intel-code from manjaro OS but you’ll boot Manjaro without intel microcode enabled
The Intel microcode updates are theoretically desirable for patches, e.g. Spectre, but unfortunately the Core 2 Duo Penryn CPU I have isn’t one of the them, says “Intel finishes Spectre patching, some older CPUs won’t receive planned updates” | Brad Chacos | April 4, 2018 at https://www.pcworld.com/article/3268007/components-processors/intel-finishes-spectre-cpu-patches-cancels-update-plans.html
After digging into trying to remove the intel-ucode, I figured out it was simpler to just use a Manjaro install DVD (or USB) to restore the Arch-Grub. This then has to be done after every Ubuntu upgrade … but is relatively straightforward (and having a Manjaro install ISO burned onto a DVD means that it’s readily at hand).
Here’s a summary of the steps I’ve used:
- With Ubuntu running, use GPartEd to confirm which partition has Manjaro installed. (In my case, it was sda11).
- Boot from the Manjaro install DVD or USB.
- When the menu appears, choose the LiveDVD option (rather than immediately (re-)installing Manjaro, which isn’t necessary).
- Open a terminal.
- Confirm the partition with Manjaro installed:
$ sudo fdisk -l
$ lsblk -f
- Mount the Manjaro system partition (mine was sda11):
$ sudo mount /dev/sda11 /mnt
- Reinstall Arch-Grub:
$ sudo grub-install –boot-directory=/mnt/boot /dev/sda
(That’s two hyphens preceding “boot-directory”)!
This method is consistent with the description of “Restore the GRUB Bootloader” at https://wiki.manjaro.org/index.php?title=Restore_the_GRUB_Bootloader for a BIOS (not UEFI) system.
While this procedure will have to be repeated after every Ubuntu upgrade, it’s understandable and replicable.