Manjaro Follow-up - Breaking things!

I wanted to write a quick follow-up covering how I managed to break, and then recover, everything when I went to remove my old debian partition.

Recap

To recap: I installed Manjaro alongside a Debian/sid and Windows 10 install. Each of those OSs were on their own SSDs. I went from a 128SSD with Windows installed, to adding a 256 installing Debian. Years later I split the Debian SSD into two parts - installing Manjaro on my new slice. Since my last update I have been playing around with Manjaro and having made my i3 keybindings for Kwin I've been pretty happy. But then I started breaking things.

Break stuff

I broke my Manjaro by updating my Debian (apparently). To be honest this is the one part I don't fully understand why it happened. From what I could find online I didn't setup my system to handle two separate Linux OS installs. But I was no longer able to boot directly into Manjaro without using the initramfs failover boot option. I only updated my Debian install because I was debugging something on my work install, which both run Debian/sid. (Otherwise I would've used my server which runs Debian/Stable). But considering I hadn't had any need to boot back into Debian I decided to just get rid of it!

GParted, Grub, Gotchas!

I went in knowing I'd have to fix my Grub since I'd be removing Debian, which was the OS that I configured when I first dualbooted the machine, so I assumed they were linked somehow and I would need to reinstall it. The process I followed was:

Create a GParted Live USB
Launch GParted reconfigure my partitions
Open the terminal in the live USB and reinstall Grub

The 3rd point being a bit of a "rest of the owl" I wasn't sure what to expect. GParted thankfully warns you "you're probably going to break stuff see our FAQ" which had a section on reinstalling grub. Reading that the 3rd part became:

mount the linux OS
bind the live dirs that are needed: /dir /sys /proc
chroot into the mounted folder
run grub-install <device>

But what I failed to realize (stupidly in hindsight) was the "device" is the Master Boot Record (MBR) device. So in my case Windows or /dev/sdb. I had assumed it was the device of the linux install so I tried that and got notified my EFI boot directory didn't look like an EFI partition... and from here it was rabbit holes.

Where is my EFI partition?

I have a fairly old Windows 7 install that has been upgraded to Windows 10 during this whole journey. I've been meaning to reinstall it (on a larger drive). But rather than having a few partitions on my drive (typically having a boot partition) I just have the one (and a recovery partition). Its marked as boot, and even mounted to /boot/efi I found when I was able to boot into Manjaro again. But it made no sense to me. If I needed an EFI partition, why was my efi pointed to the root of my Windows C drive? The rabbit hole consisted of:

Creating a 200MB Fat32 Boot partition
Mounting that as my efi-directory
Reinstalling grub (again on my Linux device)
Eventually getting it to boot straight into Manjaro
Modifying my /etc/fstab to mount my boot/efi to the new partition (oops)
Repeating the above steps 5 times hoping something would be different
Eventually finding in a forum that grub should be on the MBR...

The Fix and Final Steps

The fix was to basically follow the steps above but use the MBR:

Boot GParted Live USB
Properly configure any partitions (this case delete the "EFI" partition)
Mount the linux device
Bind the necessary live dirs to the linux mount
Run grub-install to the MBR device
Reboot

It was that misunderstanding about the MBR that sent me on a path, but now I at least feel semi-confident in changing around my OSs knowing how to fix Grub. But what bout the Fstab?

Like all true movie monsters, my stupidity came back for the final scare. I booted into Manjaro, from Grub! to have it crash on me. It couldn't mount one of the devices! The deleted partition! I was in the recover shell and was able to modify the Fstab to point back to the correct boot/efi device. (Thankfully I was familiar with Fstab to begin with). But editing two files in a super-low-res terminal is not my idea of fun (okay, maybe it is).

Conclusion

One of my new years resolutions was to learn more about my system. So lighting a fire I had to put out was a great way to get some more knowledge on maintence for grub/dualbooting.