I don't own that box so I can only give you generic help. You really would need to hook up a usb-uart adapter to access the uboot debug output to see what is happening.
The second thing I would say is that I have no idea what ophub builds do as they are not Armbian builds, ophub is a fork, they don't contribute to Armbian development nor do they participate in these forums. So per the Armbian amlogic TV box instructions, the boot environment must be a clean android boot environment. Installing or running any other distribution may cause Armbian to not boot. So I'd recommend either reinstalling a clean Android image to test from, or investigate any differences in boot scripts to see what might be going on. But again getting access to the new boot serial console would help a lot.