New C4 owner here. I tested first boot with emmc and the default Odroid image (I think it's Ubuntu 20 now), but am experimenting with Ubuntu 22 using the Armbian C4 desktop image on a SDHC card. Image downloaded to a Windows desktop, used 7-zip to uncompress the file. Used etcher (balenaetcher) to install. SHDC card is a 32GB Sandisk "A1" card. note - 1st boot took a few minutes to get going. Make sure the emmc is NOT installed when trying to boot from SDHC card (there may be a way to select which is preferred boot media but I am not up to that point yet).
