Installation of Arch Linux on a USB stick with UEFI and legacy BIOS Support

I tend to move around machines quite a bit, especially when traveling. As such, I thought it would be useful to have a portable environment on a USB stick. Since I don't know what type of machine I would be walking up to, this needed to support UEFI and BIOS. I wanted an actual install on a USB stick, not simply a live environment.

I chose Arch linux because I like the lightweight do-it-yourself philosophy and had heard good things about the pacman package manager. I had some previous experience with it as well and it was overall a positive experience. I remain concerned that the overall linux community doesn't consider arch, so updates may break things. Time will tell on this.

It took a while and I learned a ton, including that certain hardware will not work with at least the UEFI on Macs. Those that are interested, btw, should use the Samsung Flash Drive Fit instead.

I created a gist of my efforts, which I'll continue to maintain as a living document. I will not, however, include packages I install for my own use so I can keep the gist as more of a base install step-by-step.

I'm also working on making my USB multi-boot, but most other Linux distros assume during install that they should install a bootloader, etc., which would mess with my setup. I have a plan, however, so stay tuned...