Here’s how to fix your Arch Linux system if it breaks after you do a system upgrade. I suggest you bookmark this page on your smartphone so you can access this page easily even if you can’t access your computer (because it won’t boot anymore).
Sometimes, after doing a routine system update/upgrade of Archlinux it breaks. This is just the way it is, but you don’t have to reinstall everything. It’s easy to fix.
What you will need is a bootable USB or DVD/CD of the Arch ISO install program, which you can download here. Do that now and keep it around somewhere if you don’t still have your original install medium.
That being said, you have your original or backup install medium, and your Arch system breaks, here’s what to do.
1. Boot from your install medium. You’ll eventually come to a command prompt.
2. Mount the system.
mount /dev/sda1 /mnt
That “sda1” will be different strokes for different folks. On my system, for example, I have four partitions, sdc1 (/boot), sdc2 (swap), sdc3 (/) and sdc4 (/home) and I would “mount /dev/sdc3 /mnt” and then “mount /dev/sdc1 /mnt/boot” and “mount /dev/sdc4 /mnt/home”…. If you installed your Arch system you hopefully know exactly what I’m talking about.
3. arch-root /mnt
mkinitcpio -p linux
5. exit everything.
6. unmount everything.
umount -R /mnt
If you’re lucky that will fix everything. Remember, bookmark this page on your smartphone so you have a way to access this page when/if your Arch system breaks.