We are all familiar with burning live usb stick to boot our Manjaro isos. That is useful when you are installing manjaro on a new machine. However, if you already have linux installed with grub, there is a better way to boot Manjaro iso files. I usually do this when I test new iso files for a new release or when I need to use a rescue system because one of my experiments rendered my installation unbootable.

pacman --version
bash: pacman: command not found

sudo pacman -Syu --sysroot /run/media/manjaro/a09b4c60-c23f-479b-9ce2-9596ecd001b6 -b /run/media/manjaro/a09b4c60-c23f-479b-9ce2-9596ecd001b6/var/lib/pacman pacman