Hi @jock
Thank you for the hints and for your all hard work.
Finally I managed to boot the system from NAND.
After a bit digging up, I tried this gpt partition table config and bingo!
I'm happy now despite the cpu temp is a little weird for me.
Secondly, booting Armbian from USB also works like a charm. But unfortunately, Multitiool did not have that luck. I guess Multitool would require more investigate from you. I'd like to know the reason for that, too
Once again thank you and @fabiobassa as well.