OpenWrt Wireless doesn't work 2.4GHz (5GHz OK)

Hi to all.
Something strange happens on my router Archer C50 v4.
Without reasons (in appearance) sometimes my 2.4GHz stop working. No probs with my 5Ghz network.

I can connect to it but internet connection doesn't work...dhcp give me address and all seems going fine. But when I try to ping my router (which is my gateway, verified by ipconfig) it doesn't give me an answer (timeout).
Where should I search first for trying to resolve this issue ?

Thx to all !

Do you see anything weird in the logs?
logread and dmesg

Tue May 14 13:49:13 2019 daemon.notice hostapd: wlan1: AP-STA-DISCONNECTED 30:07:XX:XX:XX:XX
Tue May 14 13:49:13 2019 daemon.info hostapd: wlan1: STA 30:07:XX:XX:XX:XX IEEE 802.11: disassociated
Tue May 14 13:49:14 2019 daemon.info hostapd: wlan0: STA 30:07:XX:XX:XX:XX IEEE 802.11: authenticated
Tue May 14 13:49:14 2019 daemon.info hostapd: wlan0: STA 30:07:XX:XX:XX:XX IEEE 802.11: associated (aid 1)
Tue May 14 13:49:14 2019 daemon.notice hostapd: wlan0: AP-STA-CONNECTED 30:07:4d:00:0d:f9
Tue May 14 13:49:14 2019 daemon.info hostapd: wlan0: STA 30:07:XX:XX:XX:XX RADIUS: starting accounting session 3FC5B1C6F3BA081A
Tue May 14 13:49:14 2019 daemon.info hostapd: wlan0: STA 30:07:XX:XX:XX:XX WPA: pairwise key handshake completed (RSN)
Tue May 14 13:49:14 2019 daemon.info hostapd: wlan1: STA 30:07:XX:XX:XX:XX IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Tue May 14 13:49:15 2019 daemon.info dnsmasq-dhcp[1238]: DHCPDISCOVER(br-lan) 30:07:XX:XX:XX:XX
Tue May 14 13:49:15 2019 daemon.info dnsmasq-dhcp[1238]: DHCPOFFER(br-lan) 192.168.1.150 30:07:XX:XX:XX:XX
Tue May 14 13:49:15 2019 daemon.info dnsmasq-dhcp[1238]: DHCPREQUEST(br-lan) 192.168.1.150 30:07:XX:XX:XX:XX
Tue May 14 13:49:15 2019 daemon.info dnsmasq-dhcp[1238]: DHCPACK(br-lan) 192.168.1.150 30:07:XX:XX:XX:XX AlbiChevreS8
[May 2 20:30] mt76x2e 0000:01:00.0: MCU message 31 (seq 2) timed out
[May 2 20:32] mt76x2e 0000:01:00.0: MCU message 31 (seq 4) timed out
[  +2.079961] mt76x2e 0000:01:00.0: MCU message 31 (seq 5) timed out
[  +2.079984] mt76x2e 0000:01:00.0: MCU message 31 (seq 6) timed out
[May 3 15:20] mt76x2e 0000:01:00.0: MCU message 31 (seq 12) timed out
[  +2.079986] mt76x2e 0000:01:00.0: MCU message 31 (seq 13) timed out
[  +2.080019] mt76x2e 0000:01:00.0: MCU message 31 (seq 14) timed out
[  +2.080107] mt76x2e 0000:01:00.0: MCU message 31 (seq 15) timed out
[  +2.079834] mt76x2e 0000:01:00.0: MCU message 31 (seq 1) timed out
[  +2.079981] mt76x2e 0000:01:00.0: MCU message 31 (seq 2) timed out
[  +2.079996] mt76x2e 0000:01:00.0: MCU message 31 (seq 3) timed out
[  +2.080019] mt76x2e 0000:01:00.0: MCU message 31 (seq 4) timed out
[May 3 15:21] mt76x2e 0000:01:00.0: MCU message 31 (seq 5) timed out
[  +2.079988] mt76x2e 0000:01:00.0: MCU message 31 (seq 6) timed out
[  +2.079980] mt76x2e 0000:01:00.0: MCU message 31 (seq 7) timed out
[  +2.079991] mt76x2e 0000:01:00.0: MCU message 31 (seq 8) timed out
[  +2.079991] mt76x2e 0000:01:00.0: MCU message 31 (seq 9) timed out
[May 5 16:01] rt3050-esw 10110000.esw: link changed 0x03
[May 5 17:44] rt3050-esw 10110000.esw: link changed 0x01
[May14 12:20] rt3050-esw 10110000.esw: link changed 0x03
[May14 13:21] device wlan0 left promiscuous mode
[  +0.004932] br-lan: port 3(wlan0) entered disabled state
[  +1.052487] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[  +0.010863] br-lan: port 3(wlan0) entered blocking state
[  +0.005678] br-lan: port 3(wlan0) entered disabled state
[  +0.005940] device wlan0 entered promiscuous mode
[  +0.005129] br-lan: port 3(wlan0) entered blocking state
[  +0.005603] br-lan: port 3(wlan0) entered forwarding state
[  +0.169840] br-lan: port 3(wlan0) entered disabled state
[ +19.765641] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[  +0.006951] br-lan: port 3(wlan0) entered blocking state
[  +0.005581] br-lan: port 3(wlan0) entered forwarding state
[May14 13:28] rt3050-esw 10110000.esw: link changed 0x00
[  +0.261305] device wlan0 left promiscuous mode
[  +0.004914] br-lan: port 3(wlan0) entered disabled state
[  +1.113875] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[  +0.010565] br-lan: port 3(wlan0) entered blocking state
[  +0.005665] br-lan: port 3(wlan0) entered disabled state
[  +0.006053] device wlan0 entered promiscuous mode
[  +0.005151] br-lan: port 3(wlan0) entered blocking state
[  +0.005566] br-lan: port 3(wlan0) entered forwarding state
[  +0.091134] br-lan: port 3(wlan0) entered disabled state
[  +0.656871] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[  +0.006906] br-lan: port 3(wlan0) entered blocking state
[  +0.005568] br-lan: port 3(wlan0) entered forwarding state
[  +0.912556] rt3050-esw 10110000.esw: link changed 0x01
[  +0.661625] rt3050-esw 10110000.esw: link changed 0x03

Here when i try to connect to the Wifi. But I don't really understand dmesg here :thinking:

EDIT: " MCU message 31" seems to be the issue... Idk
https://github.com/openwrt/mt76/issues/142 or MCU message 31 (seq 14) timed out or https://www.spinics.net/lists/linux-wireless/msg174699.html

Have you tried changing the channel to either: 1, 6 or 11?

Yep already tried...
The problem seems to be the driver another topic here : https://patchwork.kernel.org/patch/10519641/

So I think I need to update the driver mt76x2 in my firmware but idk how to achieve it...
Here is my actual version :

root@OpenWrt:~# opkg list-installed | grep mt76x2
kmod-mt76x2 - 4.14.90+2018-12-28-3598046d-1
kmod-mt76x2-common - 4.14.90+2018-12-28-3598046d-1

EDIT: Seems to perform an update of this driver I need to update the kernel... from 4.14.90 to 4.14.118...