Can the Librem laptops boot from a USB drive to use a live OS occasionally, such as Ubuntu or Tails? If so, does that require a specific BIOS?
What do you mean by that?
Yes, plug the USB drive in, turn the librem on, hit the escape key. Then you get a boot menu, select your USB device, done.
To be able to boot from a live USB drive, does it matter whether the Librem 13 has coreboot or has Pureboot with Librem Key?
No it does not, both can boot from USB.
excellent, thanks, I greatly appreciate it.