Many Linux users who run multiple operating systems on a single machine eventually come across problems with Grub such as no such partition.
The most common one for multi-partition systems like mine is that the last OS installed always ends up on the top of Grub menu. In other words, the latest install becomes your default OS, even if you’re not sure you like it. Of course, you could wait out the boot screen with your finger over an arrow key, but wouldn’t it be nice to simply put your preferred OS back at the front of the line?
Another problem, though much more technical and potentially troublesome, is that multi-boot machines with windows often won’t install updates properly unless it re-boots directly into that system. On my laptop this meant that I’d have to boot and re-boot several times before everything was back to normal. I’ve also encountered the same on my Linux desktop. When the machine boots into the wrong OS upon restart, the sometimes the latest Linux kernel doesn’t install properly.
Now, it is possible to edit Grub from the Grub menu, but then most of us are in a whole new intimidating world of uncertainty; typing in commands we probably don’t understand. More than once I’ve had to reinstall Grub from a rescue disc because I misunderstood the commands. In fact until last night I stopped even trying to use the Grub command line; it’s just seemed far easier to just reinstall Grub and hope for the best.
Customize Grub with Grub Customizer
Recently I found a way to deal with both these problems is a single blow. I simply downloaded Grub Customizer. It’s easy to do.
On Ubuntu 20.04 and higher versions, you can use the following command to install Grub Customizer:
sudo apt install grub-customizer
For Ubuntu 18.04, you’ll have to use this PPA:
sudo add-apt-repository ppa:danielrichter2007/grub-customizer sudo apt update sudo apt install grub-customizer
Change boot order with Grub Customizer
Once you install Grub Customizer, open it up–it should appear in with your system stuff–you’ll see something like this.
Simply highlight the OS you want as default and move it up with the arrow button. Then click “save”.
A word of warning. Grub Customizer interface is a little sluggish and when the “advanced options for” folders are opened they can have many entries and so take up a lot of space. Furthermore, the arrow button will only move an entry one space at a time. So you can easily misplace your entry in an “advanced options for” folder, if you’re not careful. What you can do, however, is move an entire advanced folder all at once which is easier. It’s a bit like a jigsaw puzzle.
But if you think you’ve lost one of your OS’s don’t panic:
Zorin OS 11 isn’t gone it’s just hiding inside an “advanced options folder”.
Fix multiple reboot after Kernel update with Grub Customizer
The solution Grub Customizer has for my second glitch is a thing of beauty. Under the “general settings” simply toggle “predefined” to “previously booted entry“.
This way the machine always boots the last OS you used, regardless of Grub’s boot order. So after a kernel update, when you click restart, your machine will always restart in the right OS and your boot file will never get corrupted.
Finally, and I can’t stress this enough, always have a Grub rescue disc handy. They are easy to make and easy to use. If you do manage to completely rubbish your Grub, it will put things back to the way they were.
I’m a 59 year old fulltime landscaper and parttime PC medic. I’ve been an avid Linux user for over ten years. In that time I do not claim to have made every possible mistake, only most of them. I’m a big fan of prog rock, avantjazz and J S Bach, and enjoy reading Neal Stevenson and anything to do with the foundational problems in modern physics.