RT-AC68P Switching Channels

[westmc]

I've posted about this a few times but I've never received an answer. Figured I would try again. My RT-AC68P (currently running 384.10) will randomly switch channels on both 2.4 and 5.0 even though I have manually set them. This has been happening for years, through multiple versions of Merlin and multiple factory resets. Nothing ever gets logged. I set channels, I verify that they are being used. A day or so later, the router has suddenly switched to using the least optimal channels possible. I assume it is random, but it is almost always the most crowded channels that it will switch to. Any ideas?

Config is extremely basic. No scripts or anything out of the ordinary.

Just to clarify, the wireless settings screen will continue to show the manually set channels, but it won't match the channels actually being used. The wireless log screen (and an app on my phone) will show a different channel.

 

[Dave Parker]

Just wondering if you are restoring your settings from a saved backup after a factory default reset. If so this could be causing issues. I would recommend following the steps outlined by L&LD here in the forum and yes it may be necessary to do this more than once to get to a known stable state. I know, pain in the drain, but sometimes it's just necessary.

 

[westmc]

No, whenever I have done factory resets, I always put in the settings manually.

I'm just curious if this is more widespread and nobody notices. I find it hard to believe that I am the only one with this problem. I know the 68P is a lot less common than the 68U, so I guess it is possible that it is the router itself

 

[Dave Parker]

To be honest I rarely check mine. I live out in the middle of nowhere and don't have any close neighbors but when I do check I have noticed that my channels may have changed, usually after a firmware update. This has happened on my AC68U also. I just change them back and move on. Why this happens, no idea. Everything seems to work fine so I just ignore it. I can see that living in a crowded area could be a problem. Probably a dumb question but have you changed your default username, passwords and ssids?

 

[westmc]

Probably a dumb question but have you changed your default username, passwords and ssids?

Yes, but it isn't a question of hacking because my configured settings still show what I set it to. As you can see in the screenshots, I have it set to 11/48 but it is actually using 6/36. If I go back to the settings screen and hit save, it won't actually do anything. I would have to change it to some other value, hit save, change it back, and hit save for it to actually switch.

 

[Dave Parker]

I figured it was a dump question, doesn't look like a hacking issue. I just checked and I'm still at 6 and 149. Some 5G channels are not used in some areas of the world but couldn't tel you what or where that applies. Mine have not changed since my last reboot and that was 48 days ago. I'm going to update to Merlin 384.10 in the next day or two. Been putting it off because I plan to do a Factory reset since it's the 3rd update without doing a reset. I'll check to see if my channels change. Apologies, and Hopefully someone who has or had this issue can offer a little more information.

Update: I just flashed to Merlin 384.10 and did a factory default reset and then a minimal setup to get back online. My 2.4G channel changer to 8 and I reset it back to 6 as before. So far everything seems OK.

 

[westmc]

Are you checking the wireless log screen to see the actual channel being used or just looking at your settings screen?

 

[Dave Parker]

Are you checking the wireless log screen to see the actual channel being used or just looking at your settings screen?

I just checked the wireless log and it shows 6 and 149 as the channels in use.

 

[westmc]

I just checked to wireless log and it shows 6 and 149 as the channels in use.

I see you have the 86U and 68U, so it is either the 68P or my router specifically. Anybody else with the 68P?

 

[dave14305]

What do you see when you run this command when the channels are mismatched?

nvram show | grep chanspec

 

[cybrnook]

Use a WiFi scanning app on your phone to detect the broadcasted channel.

 

[westmc]

What do you see when you run this command when the channels are mismatched?

nvram show | grep chanspec

It shows...

wl_chanspec=11
size: 52908 bytes (12628 left)
wl0_chanspec=11
wl1_chanspec=48/80

Which is what my settings display, but is not what it is actually broadcasting on.

 

[westmc]

Use a WiFi scanning app on your phone to detect the broadcasted channel.

WIFI scanning apps confirm the channels shown under the wireless log (which does not match what it is set to).

 

[westmc]

I just set it back to 11/48 and within about 20 minutes the 2.4 channel switched back to 6.

 

[L&LD]

I just set it back to 11/48 and within about 20 minutes the 2.4 channel switched back to 6.

This is intriguing. I've never run across this myself or ever heard of it in the past.

If you want to thoroughly test the hardware itself; with the firmware you want to use/test installed: do an M&M Config (please see links in my signature below), do a very minimal/manual configuration, check the 'format the jffs on next reboot' option, reboot 3 times in the next 15 minutes (with at least a 5 to 10 minute wait before the next reboot). Finally, complete an NVRAM erase.

When the router boots up: physically unplug the power plug (don't use the power switch) from the router (not on the AC adaptor). Wait 5 minutes and plug in the power plug and boot it up.

Do another very minimal/manual configuration (all we're doing here is the bare minimum to get into the advanced settings, again). Flash the same firmware you already have loaded on the router and after it has completed, do one more cycle of 'format jffs on next reboot' (with 3 reboots) and a final NVRAM erase. Now, a final M&M Config to secure the router and connect to your ISP. Reboot the router 3 more times in the next 20 minutes (leave it 10 minutes between boots. Now, time to test. (Without doing any further customizations, enabling built-in features or using custom scripts).

Yes, this is probably too much, you may ask. But your issue is also very left field too.

If this is followed exactly, and the issue persists after following all recommended setup options in the links below (in my signature), the hardware is most likely at fault here. (Again; be sure when you're doing this testing that you're not using any other features/scripts or adjustments on the router or your device's wireless drivers).

If the testing passes at this stage, introduce your customizations one by one, while continuing to test in between. Continue until the issue shows up, or it is fully configured and glitch-free.

 

[westmc]

This is intriguing. I've never run across this myself or ever heard of it in the past.

If you want to thoroughly test the hardware itself; with the firmware you want to use/test installed: do an M&M Config (please see links in my signature below), do a very minimal/manual configuration, check the 'format the jffs on next reboot' option, reboot 3 times in the next 15 minutes (with at least a 5 to 10 minute wait before the next reboot). Finally, complete an NVRAM erase.

When the router boots up: physically unplug the power plug (don't use the power switch) from the router (not on the AC adaptor). Wait 5 minutes and plug in the power plug and boot it up.

Do another very minimal/manual configuration (all we're doing here is the bare minimum to get into the advanced settings, again). Flash the same firmware you already have loaded on the router and after it has completed, do one more cycle of 'format jffs on next reboot' (with 3 reboots) and a final NVRAM erase. Now, a final M&M Config to secure the router and connect to your ISP. Reboot the router 3 more times in the next 20 minutes (leave it 10 minutes between boots. Now, time to test. (Without doing any further customizations, enabling built-in features or using custom scripts).

Yes, this is probably too much, you may ask. But your issue is also very left field too.

If this is followed exactly, and the issue persists after following all recommended setup options in the links below (in my signature), the hardware is most likely at fault here. (Again; be sure when you're doing this testing that you're not using any other features/scripts or adjustments on the router or your device's wireless drivers).

If the testing passes at this stage, introduce your customizations one by one, while continuing to test in between. Continue until the issue shows up, or it is fully configured and glitch-free.

I did a slightly abbreviated version of your suggestion. I work in the computer field and as often as I jokingly ask "did you reboot three times?" when there is an issue, I can't bring myself to do it myself. I factory reset, formatted jffs, re-flashed, factory reset, and have been slowly adding back config changes.

So far, I have added back every setting but adaptive qos and this is the longest I've gone without it changing channels. At this point, I would have to guess that it was either the formatting of jffs (I had never tried that before) or disabling of adaptive qos that fixed it. I will try re-enabling qos after a few more days.

If it is the formatting of jffs, then I am puzzled because I have never created custom scripts or even enabled the jffs partition. I wouldn't have thought of trying that without your suggestion.