You have now found out that you're currently running a brnboot compatible firmware, accordingly you can only upgrade to a(nother) brnboot compatible firmware.
The nor marked images use a completely different flash partitioning, which depends on first replacing the OEM bootloader (brnboot) with u-boot. You can switch to the NOR variants at any time (going back is more difficult and depends on having good backups!), but it requires the full procedure of first replacing brnboot with u-boot.