Model : Archer C2

Hardware Version :

Firmware Version : 0.9.1 4.2 v0032.0 Build 160706 Rel.37961n

ISP : Movistar (300Mbps/30Mbps)

Hi
I started having random issues with the 5Ghz band probably a few firmware updates ago. The internet speed becomes unstable, sometimes just "null" (oscillating between 0KB/s and 3MB/s~) and my phone tend to decide to disconnect from the router because it finds it unstable/with no internet.


The 5Ghz device I'm using to do the test is a Google's "Nexus 5X".

When I reboot the router, 5Ghz works excellent, at least for a while, the Linkspeed between the router and my phone is 433Mbps link speed, and If I run a speedtest I can achieve 230-300Mbps (Download) / 30Mbps (Upload).
But when the problem happens, regardless the speed (433Mbps) internet becomes slow and unstable in the 5Ghz band, it constantly disconnect and speedtest can't do more than 3Mbps, sometimes 15Mbps.

I think there's something wrong with the router 5Ghz network...

I use the 5Ghz with default settings ( AUTO / AUTO ). Also tried many combinations without success, some good results in some channels/widths combinations, but none of these results are good and they are terrible compared to the performance I achieve every time I reboot the router.

(I also tried another router for a few months without having a problem with the Nexus 5X).

I decided to disable completely the 5Ghz band, so for now, I'm just using the 2.4Ghz which is slower, but stable.

My ISP's internet speed is: 300Mbps/30Mbps.

Router Firmware:
Firmware version:0.9.1 4.2 v0032.0 Build 160706 Rel.37961n
Hardware version:Archer C2 v1 00000000

Do you know if there's a way to fix this strange issue?

Regards
Sebastian.