Many use our LiveUSB image to install and repair systems. Typing all the mount commands over and over is annoying. I suggest to add a script similar to this one: https://wiki.gentoo.org/wiki/User:Genr8/ChrootMountCommands I was told there is also sys-apps/arch-chroot I have never used this one. Reproducible: Always
The handbook mentions `arch-chroot`. It should be on the LiveUSB too. Does it work for you?