Netgear WAX202 + Redmi10C No internet on WiFi5 ONLY after installing OpenWrt

[egorksv]

Hi All

Have a bit of interesting issue. I have flashed my WAX202 with OpenWrt 25.05.5 recently. Everything works fine, except that one Redmi10C phone. None of the setup is new, except OpenWrt, this exact phone worked with no issue on Wifi5 with Netgear OEM firmware.
Connecting the same phone to 2.4 network on the same device resolves the issue, so I believe certain WiFi settings on 5Ghz network are incorrect.

All other devices in the household work fine (macbook and samsung S20+) on the same 5GHz network, although these are both 802.11ax devices, whilst Redmi10C is 802.11ac.

When connecting the device, it sometimes (intermittent issues yaaay) fails to authenticate on WPA3/SAE, if successful it then takes unusually long (5-7 seconds) to obtain IP address over DHCP. Then it reports "Connected to WiFi network without internet). At this point the phone visible in LuCi with correct (as in the same as seen on the phone) IP and MAC address.

root@router:~# cat /etc/config/wireless

config wifi-device 'radio0'
	option type 'mac80211'
	option path '1e140000.pcie/pci0000:00/0000:00:01.0/0000:02:00.0'
	option channel '9'
	option band '2g'
	option htmode 'HE40'
	option cell_density '0'

config wifi-iface 'default_radio0'
	option device 'radio0'
	option network 'lan'
	option mode 'ap'
	option ssid 'wifi24'
	option encryption 'psk2'
	option ifname 'wlan24ghz'

config wifi-device 'radio1'
	option type 'mac80211'
	option path '1e140000.pcie/pci0000:00/0000:00:01.0/0000:02:00.0+1'
	option channel '60'
	option band '5g'
	option htmode 'HE80'
	option cell_density '0'
	option country 'GE'

config wifi-iface 'default_radio1'
	option device 'radio1'
	option network 'lan'
	option mode 'ap'
	option ssid 'wifi5'
	option encryption 'sae'
	option ifname 'wlan5ghz'
	option disassoc_low_ack '0'

Any help is greatly appreciated.

[psherman]

The critical difference between your 2.4G and 5G SSIDs is the encryption type.

Change the 5G radio to psk2 and see if that fixes the issue.

Beyond that, I would strongly recommend that you set both radios with the same SSID so that the client devices can connect to either band, switching as needed based on signal quality.

[egorksv]

Change the 5G radio to psk2 and see if that fixes the issue.

Ah, forgot to mention I did that already, no difference. Again, no issue was present with WPA3 on OEM firmware.

Thanks for the suggestion, but in my situation I would rather NOT do the same SSID. This is a small-ish household and 2.4G network here is really dedicated to the "old" devices like light bulbs, LED strips, TVs and guests with antique phones.

[psherman]

@egorksv

This is a small-ish household and 2.4G network here is really dedicated to the "old" devices like light bulbs, LED strips, TVs and guests with antique phones.

Older devices that only have 2.4G will, by definition, only connect to the 2.4G radio, even if the SSID is the same. The performance of the whole network tends to be better when you allow your devices to freely connect to whichever band they deem best (dynamically).

Why do you believe that the 2.4G network must have a different SSID?

[egorksv]

Why do you believe that the 2.4G network must have a different SSID?

I'd rather be alerted to my 5GHz network dropping than swearing a lot at my internet suddenly going slow AF. I live in an apartment building, 2.4GHz band is SUPER busy with 20+ different networks around, and the speed is impacted a lot, especially in the evening when everyone is back from work. Good thing they all are on provider-issued 2.4G boxes so 5G bandwidth is my personal playground with zero interference

Anyways, not to dwell on my personal networking preferences, let's just say I have a network bandwidth segregation fetish and move on

[psherman]

Well, I would say that your preference is strange here... I get the congestion issue, but you're sacrificing ease of use and general performance improvements by insisting on this method.

All that said, I think that the problem resides there since you said all other devices are working properly. I don't think this is an OpenWrt issue, per-se.
So, with that in mind, try forgetting the network from your phone and then re-adding it. Does that fix the problem?

If not, let's reset the wireless subsystem. Be sure to connect via ethernet before attempting this process:

First move the existing file somewhere else (you can copy it back later if you need).

mv /etc/config/wireless ~/

Then regenerate the wireless (default) file:

wifi

Now go back into the wifi settings and set:

• country code
• SSID(s)
• encryption type (use psk2)
• passphrase
• enable wifi

Then try connecting again.

[egorksv]

Ah okay, should've mentioned I factory reset the router and reconfigured everything from scratch, forgot and re-added the network. My suspicion at this point is that some setting on "advanced" pane has to be set - as I said, this phone worked perfectly fine with the router when it was running OEM firmware

[psherman]

I know iOS devices tend to like the DTIM interval = 3. You can also see if the short preamble option has any effect.

But I'd recommend that you search the internet for redmi10C wifi issues...

[egorksv]

@psherman

DTIM interval = 3. You can also see if the short preamble option has any effect

Wow, that actually fixed it! Not sure which one, but setting DTIM interval = 3 and disabling short preamble made it work immediately.

Thanks a lot, sir, you have officially saved my day!