I know for sure that booting from an sd card and then using dd to write the uncompressed image to the emmc device isn't what works. I'm talking about Armbian_22.02.1_Pinebook-pro_focal_current_5.15.25_xfce_desktop.img here.
Because that essentially bricked my PBP. I have the little adapter to connect the emmc to a usd slot, and using balena etcher to write to that isn't it either.
the uboot in that image prevents booting from sd automatically as well, and i didn't find any uboot documentation that made it clear how to manually boot from sd, though i did hook up a serial console. This is what it said. The LED never turned green, the display flashes once but displays no images or text.