2.4Ghz won't connect

[raven-au]

My iPad 4 (I think, anyway model is MD523X/A) won't connect to the 2.4 Ghz wifi.
I also see the same problem with iPad mini (model MGGT2X/A) and a Samsung Galaxy 10.1 (models GT-P7500).

The wireless attempt always returns to asking for a password over and again.
It sometimes (often) appears the device has associated with the router as it appears in the client list on the status page but ultimately fails to connect.

I'm currently using "OpenWrt Chaos Calmer r43860 / LuCI Master (git-15.005.65059-9edd0e4)" and have observed the same symptoms with lifehacksback's build and the OpenWrt build based on 3.14.27.

[raven-au]

Oh, settings are:

config wifi-device 'radio0'
option type 'mac80211'
option path 'soc/soc:pcie-controller/pci0000:00/0000:00:02.0/0000:02:00.0'
option hwmode '11g'
option channel '1'
option htmode 'HT40'
option txpower '20'
option country 'AU'

config wifi-iface
option device 'radio0'
option network 'lan'
option mode 'ap'
option ssid 'Varius'
option encryption 'psk2'
option key 'removed'

I have tried with WPA-PSK, WPA2-PSK forced AES, country World (00), also with HT20 and with (and without) a key that has only alphanumeric characters without any change in symptoms.

[raven-au]

I'm not sure about this any more.
I'm not having as much of a problem now.

Mostly I can associate (and get a DHCP address assigned OK) with both the 2.4 and 5Ghz bands.

On iDevices I still sometimes get an incorrect password dialog, like it thinks it's using a different authentication protocol. Stopping and starting the wireless on the router almost always fixes it.

I wonder if the switch changes in recent OpenWrt commits have made the difference.
I'm building my own images for testing.

In my setup I have a computer plugged into a wrt1900ac switch port and one of the switch ports plugged into a wireless bridge that connects to the main AP so it isn't all that common a setup. I did get the impression that my problem was the switch not forwarding packets properly leaving the wireless hanging.

So I'm closing this one.

[raven-au]

I have to re-open this issue.

I encountered a problem in my testing and tried to duplicate it using the 15th Jan Kaloz build and encountered the same problems I did when I logged this issue.

I'm not sure what the difference is between my build and this are.
What should I check to provide more information?

[raven-au]

I'm closing this issue again because now it looks like the disassoc_low_ack setting resolves this problem too.