Hi again,
to be more specific, I followed docs on armbian.com for eMMC install,
did apt-get update/upgrade/dist-upgrade dance, ran nand-sata-install script.
Script suggested only one option (docs says it should be 3 options).
In my case it was only "move system to eMMC", which I did.
I formatted sd card with fdisk, changed sd card mode in .fex file and still can
not boot with sd card in slot.