Problem with 802.11 ac/n radio when 802.11 b/g/n works fine

muffinman · October 9, 2025, 5:23pm

Hello, this is my first post to the forum. I could not find answer to this anywhere so I am posting here. I have been using OpenWrt for a few years now without any issues. But just this morning I had a very strange issue so I am posting it here.

The question is related to this router. This is my backup router, that I just now upgraded to the latest version.
Device : Netgear R6120
Target Platform: ramips/mt76x8
Firmware : OpenWrt 24.10.3 r28872-daca7c049b / LuCI openwrt-24.10 branch 25.250.61039~923f8d9

The problem I am facing is as follows - The router has two wireless radios :

radio0: MediaTek MT7628 802.11b/g/n (Channel: 1 (2.412 GHz))
radio1 : MediaTek MT76x2E 802.11ac/n (Channel: 36 (5.180 GHz))

This morning while I was working, the radio1 suddenly stopped working. Any device that was trying to connect to it said "connection failure". When I looked at the LUCI I don't see anything wrong with this radio. I am not an expert at LUCI so I am not sure what else I should be looking, I just saw that the configuration looked fine.

I tried rebooting the router, it didn't make any difference.

I have some basic Linux skills, so if someone can guide me as to how I can debug this problem either using LUCI UI or terminal I would appreciate it.

brada4 · October 9, 2025, 6:33pm

You are supposed to run identical APs (name, auth, subnet) on all radios for best connectivity

Lets check up on config

Please connect to your OpenWrt device using ssh and copy the output of the following commands and post it here using the "Preformatted text </> " button:

Remember to redact passwords, VPN keys, MAC addresses and any public IP addresses you may have:

ubus call system board
cat /etc/config/network
cat /etc/config/wireless
cat /etc/config/dhcp
cat /etc/config/firewall

muffinman · October 9, 2025, 7:04pm

Thanks for the prompt reply. I don't have identical names on all radios, I always kept them different so I could know where I am connected. I can certainly change that though in future.

Here are the results of the commands:

root@OpenWrt:~# ubus call system board
{
	"kernel": "6.6.104",
	"hostname": "OpenWrt",
	"system": "MediaTek MT7628AN ver:1 eco:2",
	"model": "Netgear R6120",
	"board_name": "netgear,r6120",
	"rootfs_type": "squashfs",
	"release": {
		"distribution": "OpenWrt",
		"version": "24.10.3",
		"revision": "r28872-daca7c049b",
		"target": "ramips/mt76x8",
		"description": "OpenWrt 24.10.3 r28872-daca7c049b",
		"builddate": "1758316778"
	}
}

root@OpenWrt:~# cat /etc/config/network

config interface 'loopback'
	option device 'lo'
	option proto 'static'
	option ipaddr '127.0.0.1'
	option netmask '255.0.0.0'

config globals 'globals'
	option ula_prefix 'fdc6:465c:2eec::/48'
	option packet_steering '1'

config device
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth0.1'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option ipaddr '192.168.1.1'
	option netmask '255.255.255.0'
	option ip6assign '60'
	list dns '9.9.9.9'
	list dns '149.112.112.112'

config device
	option name 'eth0.2'
	option macaddr 'XX:XX:XX:XX:XX:XX'

config interface 'wan'
	option device 'eth0.2'
	option proto 'dhcp'
	option peerdns '0'
	list dns '9.9.9.9'
	list dns '149.112.112.112'

config interface 'wan6'
	option device 'eth0.2'
	option proto 'dhcpv6'

config switch
	option name 'switch0'
	option reset '1'
	option enable_vlan '1'

config switch_vlan
	option device 'switch0'
	option vlan '1'
	option ports '0 1 2 3 6t'

config switch_vlan
	option device 'switch0'
	option vlan '2'
	option ports '4 6t'

config device 'DARPA_GUEST_dev'
	option type 'bridge'
	option name 'br-DARPA_GUEST'

config interface 'DARPA_GUEST'
	option proto 'static'
	option device 'br-DARPA_GUEST'
	option ipaddr '192.168.3.1'
	option netmask '255.255.255.0'

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

config wifi-device 'radio0'
	option type 'mac80211'
	option path 'platform/10300000.wmac'
	option channel '1'
	option band '2g'
	option htmode 'HT20'
	option cell_density '0'

config wifi-iface 'default_radio0'
	option device 'radio0'
	option network 'lan'
	option mode 'ap'
	option encryption 'psk2'
	option key 'XXXXXXXXXXXXXXXX'
	option ssid 'DARPA_BGN'

config wifi-device 'radio1'
	option type 'mac80211'
	option path 'pci0000:00/0000:00:00.0/0000:01:00.0'
	option channel '36'
	option band '5g'
	option htmode 'VHT80'
	option cell_density '0'

config wifi-iface 'default_radio1'
	option device 'radio1'
	option network 'lan'
	option mode 'ap'
	option ssid 'DARPA_AC'
	option encryption 'psk2'
	option key 'XXXXXXXXXXXXXXXX'

config wifi-iface 'DARPA_GUEST'
	option device 'radio0'
	option mode 'ap'
	option network 'DARPA_GUEST'
	option ssid 'DARPA_GUEST'
	option encryption 'psk2'
	option key 'XXXXXXXXXXXXXXXX'

root@OpenWrt:~# cat /etc/config/dhcp

config dnsmasq
	option domainneeded '1'
	option localise_queries '1'
	option rebind_protection '1'
	option rebind_localhost '1'
	option local '/lan/'
	option domain 'lan'
	option expandhosts '1'
	option authoritative '1'
	option readethers '1'
	option leasefile '/tmp/dhcp.leases'
	option resolvfile '/tmp/resolv.conf.d/resolv.conf.auto'
	option localservice '1'
	option ednspacket_max '1232'

config dhcp 'lan'
	option interface 'lan'
	option start '200'
	option limit '50'
	option leasetime '12h'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'

config dhcp 'wan'
	option interface 'wan'
	option ignore '1'

config odhcpd 'odhcpd'
	option maindhcp '0'
	option leasefile '/tmp/hosts/odhcpd'
	option leasetrigger '/usr/sbin/odhcpd-update'
	option loglevel '4'

config dhcp 'DARPA_GUEST'
	option interface 'DARPA_GUEST'
	option start '100'
	option limit '150'
	option leasetime '1h'
	option netmask '255.255.255.0'

root@OpenWrt:~# cat /etc/config/firewall

config defaults
	option syn_flood '1'
	option input 'ACCEPT'
	option output 'ACCEPT'
	option forward 'REJECT'

config zone
	option name 'lan'
	list network 'lan'
	option input 'ACCEPT'
	option output 'ACCEPT'
	option forward 'ACCEPT'

config zone
	option name 'wan'
	list network 'wan'
	list network 'wan6'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'
	option masq '1'
	option mtu_fix '1'

config forwarding
	option src 'lan'
	option dest 'wan'

config rule
	option name 'Allow-DHCP-Renew'
	option src 'wan'
	option proto 'udp'
	option dest_port '68'
	option target 'ACCEPT'
	option family 'ipv4'

config rule
	option name 'Allow-Ping'
	option src 'wan'
	option proto 'icmp'
	option icmp_type 'echo-request'
	option family 'ipv4'
	option target 'ACCEPT'

config rule
	option name 'Allow-IGMP'
	option src 'wan'
	option proto 'igmp'
	option family 'ipv4'
	option target 'ACCEPT'

config rule
	option name 'Allow-DHCPv6'
	option src 'wan'
	option proto 'udp'
	option dest_port '546'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-MLD'
	option src 'wan'
	option proto 'icmp'
	option src_ip 'fe80::/10'
	list icmp_type '130/0'
	list icmp_type '131/0'
	list icmp_type '132/0'
	list icmp_type '143/0'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-ICMPv6-Input'
	option src 'wan'
	option proto 'icmp'
	list icmp_type 'echo-request'
	list icmp_type 'echo-reply'
	list icmp_type 'destination-unreachable'
	list icmp_type 'packet-too-big'
	list icmp_type 'time-exceeded'
	list icmp_type 'bad-header'
	list icmp_type 'unknown-header-type'
	list icmp_type 'router-solicitation'
	list icmp_type 'neighbour-solicitation'
	list icmp_type 'router-advertisement'
	list icmp_type 'neighbour-advertisement'
	option limit '1000/sec'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-ICMPv6-Forward'
	option src 'wan'
	option dest '*'
	option proto 'icmp'
	list icmp_type 'echo-request'
	list icmp_type 'echo-reply'
	list icmp_type 'destination-unreachable'
	list icmp_type 'packet-too-big'
	list icmp_type 'time-exceeded'
	list icmp_type 'bad-header'
	list icmp_type 'unknown-header-type'
	option limit '1000/sec'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-IPSec-ESP'
	option src 'wan'
	option dest 'lan'
	option proto 'esp'
	option target 'ACCEPT'

config rule
	option name 'Allow-ISAKMP'
	option src 'wan'
	option dest 'lan'
	option dest_port '500'
	option proto 'udp'
	option target 'ACCEPT'

config zone 'DARPA_GUEST'
	option name 'DARPA_GUEST'
	option network 'DARPA_GUEST'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'

config forwarding 'DARPA_GUEST_wan'
	option src 'DARPA_GUEST'
	option dest 'wan'

config rule 'DARPA_GUEST_dns'
	option name 'Allow-DNS-DARPA_GUEST'
	option src 'DARPA_GUEST'
	option dest_port '53'
	list proto 'tcp'
	list proto 'udp'
	option target 'ACCEPT'

config rule 'DARPA_GUEST_dhcp'
	option name 'Allow-DHCP-DARPA_GUEST'
	option src 'DARPA_GUEST'
	option dest_port '67'
	option proto 'udp'
	option family 'ipv4'
	option target 'ACCEPT'

brada4 · October 9, 2025, 7:11pm

Set wifi country for more power (so far all your config is close to perfect) - no idea what is wrong there in the air. Run logread and try to determine how bad stuff started.

This is minor (but a huge problem if you do vpn or pppoe or other tunnels in future

Try to extract logread if you catch it broken,

Not related to wifi AP.

You can set quad9 servers as upstreams for dnsmasq

Network/Dns/Forwards → enter IPs.

Network/DNS/Hosts files → dont use resolv file

all set. no need to change interfaces conf.

badulesia · October 9, 2025, 7:13pm

Settings are based on default and are pretty harmless.
If I'm not wrong, this line means that the 5GHz radio is not embedded in the SoC, but use an internal wifi card linked by a bus. Could it be unplugged or somewhat ? Does the kernel log show the card when booting?

brada4 · October 9, 2025, 7:19pm

Thats normal, 2.4ghz is on chip and ac is on pci link, soldered on pcb…

badulesia · October 9, 2025, 8:15pm

I knew, that's where the problem is. OP must confirm that the bootlog shows the device, otherwise it could be unplugged, toasted or else.

muffinman · October 9, 2025, 9:29pm

Here are the kernel logs, I don't understand much here but it looks like it is booting.

[   28.355803] mt76x2e 0000:01:00.0: card - bus=0x1, slot = 0x0 irq=4
[   28.368474] mt76x2e 0000:01:00.0: ASIC revision: 76120044
[   30.124205] mt76x2e 0000:01:00.0: ROM patch build: 20141115060606a
[   30.196959] mt76x2e 0000:01:00.0: Firmware Version: 0.0.00
[   30.207937] mt76x2e 0000:01:00.0: Build: 1
[   30.216066] mt76x2e 0000:01:00.0: Build Time: 201607111443____
[   30.293320] mt76x2e 0000:01:00.0: Firmware running!
[   30.303322] mt76x2e 0000:01:00.0: registering led 'mt76-phy1'
[   30.316845] ieee80211 phy1: Selected rate control algorithm 'minstrel_ht'

brada4 · October 9, 2025, 9:31pm

Device is rather small, rise log size from 64 to 1024 (kilobytes) (luci/system) so that you have more time to react to 5GHz breaking.

Waiting on bad news from you …..

muffinman · October 9, 2025, 9:42pm

What am I looking in logread? I tried this:

logread | grep .error

There are no errors, then I tried to search for

logread | grep .warn

and I see this repeated all the time, but based on just google search this might be unrelated:

Thu Oct  9 21:37:42 2025 daemon.warn odhcpd[1487]: No default route present, overriding ra_lifetime to 0!

brada4 · October 9, 2025, 9:45pm

logread -e hostap

logread -e DHCP

nothing wrong not having ip6 today, it will come and error will go away

badulesia · October 9, 2025, 9:46pm

Seach for this, and copy/paste near lines.

muffinman · October 9, 2025, 10:04pm

Just so that you know before running this I did change the channel to 40 and also set the country code. So you might notice logs related to that:

Thu Oct  9 21:45:37 2025 daemon.notice hostapd: phy0-ap0: AP-STA-DISCONNECTED xx:xx:xx:xx:xx:xx
Thu Oct  9 21:45:37 2025 daemon.info hostapd: phy0-ap0: STA xx:xx:xx:xx:xx:xx IEEE 802.11: disassociated
Thu Oct  9 21:45:38 2025 daemon.info hostapd: phy0-ap0: STA xx:xx:xx:xx:xx:xx IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Thu Oct  9 21:45:42 2025 daemon.info hostapd: phy0-ap0: STA yy:yy:yy:yy:yy:yy IEEE 802.11: authenticated
Thu Oct  9 21:45:42 2025 daemon.info hostapd: phy0-ap0: STA yy:yy:yy:yy:yy:yy IEEE 802.11: associated (aid 2)
Thu Oct  9 21:45:42 2025 daemon.notice hostapd: phy0-ap0: AP-STA-CONNECTED yy:yy:yy:yy:yy:yy auth_alg=open
Thu Oct  9 21:45:42 2025 daemon.info hostapd: phy0-ap0: STA yy:yy:yy:yy:yy:yy WPA: pairwise key handshake completed (RSN)
Thu Oct  9 21:45:42 2025 daemon.notice hostapd: phy0-ap0: EAPOL-4WAY-HS-COMPLETED yy:yy:yy:yy:yy:yy
Thu Oct  9 21:51:33 2025 daemon.notice hostapd: Set new config for phy phy1: /var/run/hostapd-phy1.conf
Thu Oct  9 21:51:33 2025 daemon.notice hostapd: Restart interface for phy phy1
Thu Oct  9 21:51:33 2025 daemon.notice hostapd: Remove interface 'phy1'
Thu Oct  9 21:51:33 2025 daemon.notice hostapd: phy1-ap0: interface state ENABLED->DISABLED
Thu Oct  9 21:51:33 2025 daemon.notice hostapd: phy1-ap0: AP-DISABLED
Thu Oct  9 21:51:33 2025 daemon.notice hostapd: phy1-ap0: CTRL-EVENT-TERMINATING
Thu Oct  9 21:51:33 2025 daemon.notice hostapd: nl80211: deinit ifname=phy1-ap0 disabled_11b_rates=0
Thu Oct  9 21:51:34 2025 daemon.notice hostapd: nl80211: wpa_driver_nl80211_event_receive->nl_recvmsgs failed: -5
Thu Oct  9 21:51:34 2025 daemon.notice hostapd: Configuration file: <inline> (phy phy1) --> new PHY
Thu Oct  9 21:51:34 2025 daemon.notice hostapd: Configuration file: Reading configuration file '<inline>'
Thu Oct  9 21:51:35 2025 daemon.notice hostapd: phy1-ap0: interface state UNINITIALIZED->COUNTRY_UPDATE
Thu Oct  9 21:51:35 2025 daemon.notice hostapd: phy1-ap0: interface state COUNTRY_UPDATE->HT_SCAN
Thu Oct  9 21:51:36 2025 daemon.notice hostapd: Switch own primary and secondary channel to get secondary channel with no Beacons from other BSSes
Thu Oct  9 21:51:37 2025 daemon.notice hostapd: phy1-ap0: interface state HT_SCAN->ENABLED
Thu Oct  9 21:51:37 2025 daemon.notice hostapd: phy1-ap0: AP-ENABLED
Thu Oct  9 21:52:41 2025 daemon.notice hostapd: phy0-ap0: AP-STA-DISCONNECTED yy:yy:yy:yy:yy:yy
Thu Oct  9 21:52:41 2025 daemon.info hostapd: phy0-ap0: STA yy:yy:yy:yy:yy:yy IEEE 802.11: disassociated
Thu Oct  9 21:52:42 2025 daemon.info hostapd: phy0-ap0: STA yy:yy:yy:yy:yy:yy IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Thu Oct  9 21:52:46 2025 daemon.info hostapd: phy0-ap0: STA zz:zz:zz:zz:zz:zz IEEE 802.11: authenticated
Thu Oct  9 21:52:46 2025 daemon.info hostapd: phy0-ap0: STA zz:zz:zz:zz:zz:zz IEEE 802.11: associated (aid 2)
Thu Oct  9 21:52:46 2025 daemon.notice hostapd: phy0-ap0: AP-STA-CONNECTED zz:zz:zz:zz:zz:zz auth_alg=open
Thu Oct  9 21:52:46 2025 daemon.info hostapd: phy0-ap0: STA zz:zz:zz:zz:zz:zz WPA: pairwise key handshake completed (RSN)
Thu Oct  9 21:52:46 2025 daemon.notice hostapd: phy0-ap0: EAPOL-4WAY-HS-COMPLETED zz:zz:zz:zz:zz:zz

Thu Oct  9 21:45:46 2025 daemon.info dnsmasq-dhcp[2688]: DHCPDISCOVER(br-lan) aa:aa:aa:aa:aa:aa
Thu Oct  9 21:45:46 2025 daemon.info dnsmasq-dhcp[2688]: DHCPOFFER(br-lan) 192.168.1.202 aa:aa:aa:aa:aa:aa
Thu Oct  9 21:45:46 2025 daemon.info dnsmasq-dhcp[2688]: DHCPDISCOVER(br-lan) aa:aa:aa:aa:aa:aa
Thu Oct  9 21:45:46 2025 daemon.info dnsmasq-dhcp[2688]: DHCPOFFER(br-lan) 192.168.1.202 aa:aa:aa:aa:aa:aa
Thu Oct  9 21:45:46 2025 daemon.info dnsmasq-dhcp[2688]: DHCPDISCOVER(br-lan) aa:aa:aa:aa:aa:aa
Thu Oct  9 21:45:46 2025 daemon.info dnsmasq-dhcp[2688]: DHCPOFFER(br-lan) 192.168.1.202 aa:aa:aa:aa:aa:aa
Thu Oct  9 21:45:46 2025 daemon.info dnsmasq-dhcp[2688]: DHCPREQUEST(br-lan) 192.168.1.202 aa:aa:aa:aa:aa:aa
Thu Oct  9 21:45:46 2025 daemon.info dnsmasq-dhcp[2688]: DHCPACK(br-lan) 192.168.1.202 aa:aa:aa:aa:aa:aa
Thu Oct  9 21:46:18 2025 daemon.info dnsmasq-dhcp[2688]: DHCPREQUEST(br-DARPA_GUEST) 192.168.3.105 bb:bb:bb:bb:bb:bb
Thu Oct  9 21:46:18 2025 daemon.info dnsmasq-dhcp[2688]: DHCPACK(br-DARPA_GUEST) 192.168.3.105 bb:bb:bb:bb:bb:bb tv
Thu Oct  9 21:51:32 2025 daemon.info dnsmasq[6682]: compile time options: IPv6 GNU-getopt no-DBus UBus no-i18n no-IDN DHCP no-DHCPv6 no-Lua TFTP no-conntrack no-ipset no-nftset no-auth no-cryptohash no-DNSSEC no-ID loop-detect inotify dumpfile
Thu Oct  9 21:51:32 2025 daemon.info dnsmasq-dhcp[6682]: DHCP, IP range 192.168.3.100 -- 192.168.3.249, lease time 1h
Thu Oct  9 21:51:32 2025 daemon.info dnsmasq-dhcp[6682]: DHCP, IP range 192.168.1.200 -- 192.168.1.249, lease time 12h
Thu Oct  9 21:51:35 2025 daemon.info dnsmasq-dhcp[6682]: DHCPDISCOVER(br-lan) 192.168.1.243 cc:cc:cc:cc:cc:cc
Thu Oct  9 21:51:35 2025 daemon.info dnsmasq-dhcp[6682]: DHCPOFFER(br-lan) 192.168.1.243 cc:cc:cc:cc:cc:cc
Thu Oct  9 21:51:35 2025 daemon.info dnsmasq-dhcp[6682]: DHCPREQUEST(br-lan) 192.168.1.243 cc:cc:cc:cc:cc:cc
Thu Oct  9 21:51:35 2025 daemon.info dnsmasq-dhcp[6682]: DHCPACK(br-lan) 192.168.1.243 cc:cc:cc:cc:cc:cc pc
Thu Oct  9 21:51:52 2025 daemon.info dnsmasq[7156]: compile time options: IPv6 GNU-getopt no-DBus UBus no-i18n no-IDN DHCP no-DHCPv6 no-Lua TFTP no-conntrack no-ipset no-nftset no-auth no-cryptohash no-DNSSEC no-ID loop-detect inotify dumpfile
Thu Oct  9 21:51:52 2025 daemon.info dnsmasq-dhcp[7156]: DHCP, IP range 192.168.3.100 -- 192.168.3.249, lease time 1h
Thu Oct  9 21:51:52 2025 daemon.info dnsmasq-dhcp[7156]: DHCP, IP range 192.168.1.200 -- 192.168.1.249, lease time 12h
Thu Oct  9 21:52:51 2025 daemon.info dnsmasq-dhcp[7156]: DHCPDISCOVER(br-lan) dd:dd:dd:dd:dd:dd
Thu Oct  9 21:52:51 2025 daemon.info dnsmasq-dhcp[7156]: DHCPOFFER(br-lan) 192.168.1.203 dd:dd:dd:dd:dd:dd
Thu Oct  9 21:52:51 2025 daemon.info dnsmasq-dhcp[7156]: DHCPDISCOVER(br-lan) dd:dd:dd:dd:dd:dd
Thu Oct  9 21:52:51 2025 daemon.info dnsmasq-dhcp[7156]: DHCPOFFER(br-lan) 192.168.1.203 dd:dd:dd:dd:dd:dd
Thu Oct  9 21:52:51 2025 daemon.info dnsmasq-dhcp[7156]: DHCPDISCOVER(br-lan) dd:dd:dd:dd:dd:dd
Thu Oct  9 21:52:51 2025 daemon.info dnsmasq-dhcp[7156]: DHCPOFFER(br-lan) 192.168.1.203 dd:dd:dd:dd:dd:dd
Thu Oct  9 21:52:51 2025 daemon.info dnsmasq-dhcp[7156]: DHCPREQUEST(br-lan) 192.168.1.203 dd:dd:dd:dd:dd:dd
Thu Oct  9 21:52:51 2025 daemon.info dnsmasq-dhcp[7156]: DHCPACK(br-lan) 192.168.1.203 dd:dd:dd:dd:dd:dd

muffinman · October 9, 2025, 10:11pm

I increased the log size as well, not sure whether or where it made the difference.

brada4 · October 9, 2025, 10:34pm

You have to wait for problem. If you have some log filtering solution tune it to ignore “normal” events.

muffinman · October 9, 2025, 10:50pm

The problem is that, my android can "see" this wifi but when I try to connect it just says connection failure. At that time when I look for logs in the router, it is as if nobody tried to connect. It is getting late here for me, so I will check back here tomorrow morning. I appreciate all the help so far. Thank you.

psherman · October 10, 2025, 2:55am

You have a guest network and a normal lan... does the android device have difficulty connecting to one of these networks or both?

hecatae · October 10, 2025, 9:35am

Does that apply to 802.11s mesh networks as well?

hecatae · October 10, 2025, 9:36am

What country are you in, and what country have you set on the radio, as I cannot see it on the configuration?

muffinman · October 10, 2025, 11:52am

Guest network is on bgn radio so no problem with that.

Canada.