In this case(N66U), the icon is only showing the control channel, no width.
That's odd. My N66U shows 165/20MHz here. It must only occur under certain specific circumstances.
Okay that's good to know. Either mtd-erase -d nvram is not completely erasing the nvram or my bootloader's domain info in 5GHz has changed after flushing to 1.4 bootloader. I have defaulted the settings using the mtd method but after the reset, I've notice the time zone(eastern time) didn't change so it seems the factory reset didn't completely erased the nvram. I'm thinking the bootloader could have not done these since the 2.4/5GHz domains have different country codes, it should be the same?
If you changed the CFE then that's likely the source. Try checking what values are in the CFE. An example here:
Code:
cat /dev/mtd0ro | grep regulation_domain_5G
You can grep the other regional settings that way to see what's in CFE. Those are what will get applied at boot time, regardless of what's in nvram.