Booting a image from an SD card on a #librem5. In this case #postmarketos. Got to play again with some work in progress code made by #librem5 developers. In this case a u-boot image that allows the #librem5 to boot from the SD cacrd. It can boot from the SD directly, but the video first I booted the #pureos image in the eMMC and then rebooted and booted #postmarketos from the SD card. Credits to the #librem5 devs and to @craftyguy for making the #pmos image for the SD card to test this :D
Forgot to mention, to select booting from the eMMC or the SD card you don't need to remove or insert the SD card. You just need to press the correct key combo on boot.