Xiaomi Redmi AC2100 and 5GHz networks

[GuyKhmel]

I installed the snapshot build for Xiaomi Redmi AC2100 and everything works but often my 5G wireless network doesn't work / even show...

I got two phenomenons going on - both happening some time after a working 5G network runs:

1. Very often - the 5Ghz network doesn't even show - I've attached an image of the view, it's enabled and should be working but doesn't appear in any of the devices I see
2. In other cases, I can connect, get a DHCP address, but nothing works, not even ping to 192.168.1.1 even though the network is connected (tested on laptop and phone).

I tried changing the bandwidth from 160Mhz to 80Mhz and now 40.
Tried to change the channels.
Tried to change the country (I'm from Israel, but tried US, Europe...) - didn't help
Tried to restart the MediaTek MT7615E 802.11nac radio device - Partially helped - on some devices this started to work while in others it doesn't but again after some time was back to not working.

Need to mention that 2.4Ghz works flawlessly during these case.

cat /etc/config/wireless
 
config wifi-device 'radio0'
        option type 'mac80211'
        option channel '11'
        option hwmode '11g'
        option path '1e140000.pcie/pci0000:00/0000:00:01.0/0000:02:00.0'
        option country 'US'
        option htmode 'HT40'
 
config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option key 'password'
        option encryption 'psk-mixed'
        option ssid 'OpenWRT'
 
config wifi-device 'radio1'
        option type 'mac80211'
        option hwmode '11a'
        option path '1e140000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0'
        option legacy_rates '0'
        option channel '100'
        option htmode 'VHT160'
        option country 'US'
 
config wifi-iface 'default_radio1'
        option device 'radio1'
        option network 'lan'
        option mode 'ap'
        option key 'password'
        option encryption 'psk-mixed'
        option ssid 'OpenWRT_5G'
        option disassoc_low_ack '0'

Any help or ideas for extra data?

[arkaild]

I have the same problem with wireless 5G. 2.4 is Ok

[GuyKhmel]

I ended up flashing the original MiWifi rom again and again reflashing the latest OpenWRT snapshot - it seems to be working right and 5Ghz network is stable for two days now...

[tmomas]

If your problem is solved, please consider marking this topic as [Solved]. See How to mark a topic as [Solved] for a short how-to.

[GuyKhmel]

I did some deeper investigation and got some more details.

After changing to a channel - I looked in the tab system queue and saw the following line:

Configured channel (165) or frequency (5825) not found from the channel list of the current mode (2) IEEE 802.11a

After this - I connected by SSH to the router and ran iw list

Got this (filtering to the only relevant part):

		Frequencies:
			* 5180 MHz [36] (23.0 dBm)
			* 5200 MHz [40] (23.0 dBm)
			* 5220 MHz [44] (23.0 dBm)
			* 5240 MHz [48] (23.0 dBm)
			* 5260 MHz [52] (23.0 dBm) (radar detection)
			* 5280 MHz [56] (23.0 dBm) (radar detection)
			* 5300 MHz [60] (23.0 dBm) (radar detection)
			* 5320 MHz [64] (23.0 dBm) (radar detection)
			* 5500 MHz [100] (disabled)
			* 5520 MHz [104] (disabled)
			* 5540 MHz [108] (disabled)
			* 5560 MHz [112] (disabled)
			* 5580 MHz [116] (disabled)
			* 5600 MHz [120] (disabled)
			* 5620 MHz [124] (disabled)
			* 5640 MHz [128] (disabled)
			* 5660 MHz [132] (disabled)
			* 5680 MHz [136] (disabled)
			* 5700 MHz [140] (disabled)
			* 5720 MHz [144] (disabled)
			* 5745 MHz [149] (disabled)
			* 5765 MHz [153] (disabled)
			* 5785 MHz [157] (disabled)
			* 5805 MHz [161] (disabled)
			* 5825 MHz [165] (disabled)
			* 5845 MHz [169] (disabled)
			* 5865 MHz [173] (disabled)

This list is a combination of the country code and the device capabilities.
I then changed the country to US and ran this again.
Got the following list:

		Frequencies:
			* 5180 MHz [36] (23.0 dBm)
			* 5200 MHz [40] (23.0 dBm)
			* 5220 MHz [44] (23.0 dBm)
			* 5240 MHz [48] (23.0 dBm)
			* 5260 MHz [52] (23.0 dBm) (radar detection)
			* 5280 MHz [56] (23.0 dBm) (radar detection)
			* 5300 MHz [60] (23.0 dBm) (radar detection)
			* 5320 MHz [64] (23.0 dBm) (radar detection)
			* 5500 MHz [100] (23.0 dBm) (radar detection)
			* 5520 MHz [104] (23.0 dBm) (radar detection)
			* 5540 MHz [108] (23.0 dBm) (radar detection)
			* 5560 MHz [112] (23.0 dBm) (radar detection)
			* 5580 MHz [116] (23.0 dBm) (radar detection)
			* 5600 MHz [120] (23.0 dBm) (radar detection)
			* 5620 MHz [124] (23.0 dBm) (radar detection)
			* 5640 MHz [128] (23.0 dBm) (radar detection)
			* 5660 MHz [132] (23.0 dBm) (radar detection)
			* 5680 MHz [136] (23.0 dBm) (radar detection)
			* 5700 MHz [140] (23.0 dBm) (radar detection)
			* 5720 MHz [144] (23.0 dBm) (radar detection)
			* 5745 MHz [149] (26.0 dBm)
			* 5765 MHz [153] (26.0 dBm)
			* 5785 MHz [157] (26.0 dBm)
			* 5805 MHz [161] (26.0 dBm)
			* 5825 MHz [165] (26.0 dBm)
			* 5845 MHz [169] (disabled)
			* 5865 MHz [173] (disabled)

I selected channel 149 - and it all seems to be working.

Note that you shouldn't select radar detection channels