5Ghz Stops Broadcasting on Merlin 380.68_2 and above - AC3100

[webgrease]

For many many years I've followed the Asuswrt-Merlin forums and laughed or rolled my eyes at all the posts where people complained of wireless problems after upgrading firmware, and nearly every time it turns out they missed a step or were the only one experiencing the issue. After searching the forums for the current problem I'm having, I'm afraid I'm now "that guy".

Before I explain the issue, wanted to just point out that I have always gone way overboard when flashing to make absolute certain it was a clean install; flash firmware, reset to factory settings after login, 30-30-30, set to recovery mode, reflash using Asus firmware restoration utility, manually reconfigure all router settings, reboot.

Handed off an old trusty AC68U to a family member back in June and got an AC3100. Immediately flashed with 380.66_4. Worked great for months, no issues. Had some major ISP problems in mid-September and used the downtime to flash 380.68_2. Over time, starting noticing that the 5Ghz signal would stop broadcasting. All devices in the house would lose connectivity, so it was pretty obvious when it would happen. Checked inSSIDer, there was no 5Ghz being broadcast within range at all. No problems at all with 2.4Ghz. Checked the router and logs, nothing indicated any issue. First few times assumed it was a fluke, rebooted the router, and it worked again. Over time, the frequency of 5Ghz dropping out increased, and as of the last few days, it wouldn't stay up for more than a hour or two. Never had an issue with Merlin firmware, so figured it was most likely a hardware issue and dreaded sending it in to Asus for a warranty exchange, only to end up with a refurb.

Being in the IT field, I knew I had to run several tests to rule out firmware before contacting them. I flashed back down to 380.68_0 using my overblown method above, same problem. Flashed back down to 380.67_0, same problem. Flashed back down to 380.66_6, same problem. Seeing as this was going nowhere, and knowing I'd have to send the router back on a stock firmware, I flashed to the official Asus RT-AC3100_3.0.0.4_382_15852, and much to my shock and surprise, I've been up and running for 85+ hours without a single issue.

When I get some free time, I plan on testing two more things; 1) reflashing 380.68_2 and see if it now works (which I'm guessing it won't), and if it doesn't, 2) reflash back to 380.66_4, the last known working Merlin firmware I had running.

I have chills of disgust knowing I'm running on stock firmware and not Merlin. Anyone else experiencing similar issues? Any idea what is going on? I needs me some Merlin firmware!! And THANK YOU, Merlin, for all your hard work over the years - very much appreciated!

 

[skeal]

I think off the top your flashing technique is flawed. Don't use the 30-30-30 method for a firmware update. Just upload the new firmware reset to factory defaults in the GUI and manually configure from there. Try this simpler technique when you flash from stock to merlin 380.68_2. Do not flash twice it is not necessary.

 

[KevTech]

I think off the top your flashing technique is flawed. Don't use the 30-30-30 method for a firmware update.

Ya 30-30-30 is for DD-WRT only.

Merlin even states this: https://github.com/RMerl/asuswrt-merlin/wiki/Installation

 

[webgrease]

I understand that my flash method is inconvenient, long and unnecessary, but it would have no bearing on my issue nor a firmware being correctly applied to the router.

 

[Kruegs]

Your post is an exact copy of my situation... same thing to a "T" including flashing back to stock Asus FW which restored the stability in the 5Ghz band. I reached out to Asus reluctantly thinking a long RMA process would ensue. I ended up with the following suggestion from one of their techs which seems to have solved mine so far. I am going on day 7 after making these changes and it has been rock solid. I am currently also on Merlin 380.68_2 which I flashed back to prior to making these changes. The only other thing I did after going back to Merlin was to do a factory reset through the GUI.

1. Wireless -> General -> 5GHz-1 or 5GHz-2 -> Select 'Legacy', 'N only' or 'N/AC mixed' in Wireless Mode

2. Change channel bandwidth to '40 MHz' (Wireless -> General -> Band = 5GHz-1 or 5GHz-2)

3. Wireless -> Professional -> 5GHz-1 or 5GHz-2 -> disable Explicit beam forming and Universal Beam forming

I cannot tell you which one of these, or the combo of them seemingly corrected the issue with 5Ghz dropping... but (knock on wood) hopefully the situation is resolved. Best of luck!

Regards

 

[skeal]

I understand that my flash method is inconvenient, long and unnecessary, but it would have no bearing on my issue nor a firmware being correctly applied to the router.

Suit your self but it would. I own the same router as you. When I upgraded from stock to merlin I had trouble. The secret ended up being the flash and what I did after. My procedure was to flash the router in the web GUI then I pressed the button on the back called reset (because) a GUI reset was not working for some unknown reason. This worked in the end. But it was the third attempt. On the way I had some really strange problems until I did the above procedure. Each attempt to flash appeared to be successful by the way so I would not assume that your excessive upgrade method would be any different. The other thing is the forum is not swamped with your problem. See post #3.
Regards.

 

[doczenith1]

One thing that I didn't see in your flashing process was a complete power down of the router by unplugging the power cord for a few minutes after the upgrade and reset. I have read posts on this site where some say that in rare occasions this resets certain components in the router that don't fully reset during a reset/reboot. Might be worth a try. I've also heard that a second flash of the same firmware after the initial flash and reset will sometimes kill the gremlins

Regarding beamforming. On the 5 GHz band Merlin has suggested to disable universal beamforming but keep explicit beamforming (now called 802.11ac Beamforming on newer firmwares) as 802.11ac Beamforming is part of the ac spec.

Also worth mentioning. On Merlin's 380.66 changlog he states: "If you are experiencing new wifi stability issues, try disabling Airtime Fairness on the Wireless -> Professional page (on all bands)." I'm not certain but I believe this advice applies to later firmwares as well.

 

[jumpycalm]

I am using RT-AC88U which is the same router as RT-AC3100 plus a 4 port switch. I am getting exact same problem as webgrease, I tried to reset the router (cleared jffs portion and reseted from GUI) and no help. I got disconnected at least 1 or twice a day. The issue started occur about over a month ago. I had the router for about 2 months already. There's are lots of similar issue reported on SNB but looks like none of them had a solution.

I tried Kruegs's suggestion. I changed 5GHz bandwidth to 80Hz, I also changed the channel to a fixed channel. I disabled Universal Beamforming only as 802.11ac beamforming will disable MU-MIMO which I don't want. I will wait and see if this can resolve the issue.

 

[webgrease]

Your post is an exact copy of my situation... same thing to a "T" including flashing back to stock Asus FW which restored the stability in the 5Ghz band. I reached out to Asus reluctantly thinking a long RMA process would ensue. I ended up with the following suggestion from one of their techs which seems to have solved mine so far. I am going on day 7 after making these changes and it has been rock solid. I am currently also on Merlin 380.68_2 which I flashed back to prior to making these changes. The only other thing I did after going back to Merlin was to do a factory reset through the GUI.

1. Wireless -> General -> 5GHz-1 or 5GHz-2 -> Select 'Legacy', 'N only' or 'N/AC mixed' in Wireless Mode

2. Change channel bandwidth to '40 MHz' (Wireless -> General -> Band = 5GHz-1 or 5GHz-2)

3. Wireless -> Professional -> 5GHz-1 or 5GHz-2 -> disable Explicit beam forming and Universal Beam forming

I cannot tell you which one of these, or the combo of them seemingly corrected the issue with 5Ghz dropping... but (knock on wood) hopefully the situation is resolved. Best of luck!

Regards

Very glad to hear I'm not the only one with this issue.

Interesting... what doesn't make sense to me is if one of those items really does fix the issue, why all of a sudden do these default values that we've been using forever now cause this problem? Is one of those default values (or functions it controls) now corrupt? We'd essentially be using the router at less than its full capacity/capability. Please keep us in the loop with your situation. Thanks!

 

[webgrease]

One thing that I didn't see in your flashing process was a complete power down of the router by unplugging the power cord for a few minutes after the upgrade and reset. I have read posts on this site where some say that in rare occasions this resets certain components in the router that don't fully reset during a reset/reboot. Might be worth a try. I've also heard that a second flash of the same firmware after the initial flash and reset will sometimes kill the gremlins

Regarding beamforming. On the 5 GHz band Merlin has suggested to disable universal beamforming but keep explicit beamforming (now called 802.11ac Beamforming on newer firmwares) as 802.11ac Beamforming is part of the ac spec.

Also worth mentioning. On Merlin's 380.66 changlog he states: "If you are experiencing new wifi stability issues, try disabling Airtime Fairness on the Wireless -> Professional page (on all bands)." I'm not certain but I believe this advice applies to later firmwares as well.

That would have occurred during the 2nd "30" in the 30-30-30 step, which is after the first flash of the firmware. I could always add an unplug/replug to my already endless process, but doubt it would do any good.

Thank you for the info on Beamforming, I'll do some more research there.

I'd have to go back and look, but I'm pretty sure that Airtime Fairness is disabled by default and I have never enabled that in the past.

Thanks again for your input... this looks promising.

 

[webgrease]

I am using RT-AC88U which is the same router as RT-AC3100 plus a 4 port switch. I am getting exact same problem as webgrease, I tried to reset the router (cleared jffs portion and reseted from GUI) and no help. I got disconnected at least 1 or twice a day. The issue started occur about over a month ago. I had the router for about 2 months already. There's are lots of similar issue reported on SNB but looks like none of them had a solution.

I tried Kruegs's suggestion. I changed 5GHz bandwidth to 80Hz, I also changed the channel to a fixed channel. I disabled Universal Beamforming only as 802.11ac beamforming will disable MU-MIMO which I don't want. I will wait and see if this can resolve the issue.

Please report back if your issues have cleared up with your changes. The more info we have out here, the better. Thanks

 

[jumpycalm]

It's been over a day after I made the change, and I haven't seen my 5GHz signal drop. Looks like Kruegs's suggestion works. I definitely need more time to test, but so far so good, my 5GHz never survived more than 1 day in the last couple weeks!
What I did resolved my issue was: 1. I changed 5GHz bandwidth to 80Hz instead of 20MHz/40MHz/80MHz auto select; 2. I also changed the channel to a fixed channel instead of auto select; 3. I disabled Universal Beamforming in advanced setting.

 

[ScottW]

It's been over a day after I made the change, and I haven't seen my 5GHz signal drop. Looks like Kruegs's suggestion works. I definitely need more time to test, but so far so good, my 5GHz never survived more than 1 day in the last couple weeks!
What I did resolved my issue was: 1. I changed 5GHz bandwidth to 80Hz instead of 20MHz/40MHz/80MHz auto select; 2. I also changed the channel to a fixed channel instead of auto select; 3. I disabled Universal Beamforming in advanced setting.

I had this problem (5g completely disappearing) with my AC88U, spanning multiple versions of both Asus and Merlin firmware. What fixed it for me was setting bandwidth to fixed 40MHz (I always used fixed channel as well). Setting to fixed 80MHz did not solve it for me (although sometimes it would go almost a week before dropping). More info in the following post, from a thread clear back in May about the same problem.
https://www.snbforums.com/threads/random-net-loss-5g-going-down.37657/page-4#post-328166

 

[jumpycalm]

I had this problem (5g completely disappearing) with my AC88U, spanning multiple versions of both Asus and Merlin firmware. What fixed it for me was setting bandwidth to fixed 40MHz (I always used fixed channel as well). Setting to fixed 80MHz did not solve it for me (although sometimes it would go almost a week before dropping). More info in the following post, from a thread clear back in May about the same problem.
https://www.snbforums.com/threads/random-net-loss-5g-going-down.37657/page-4#post-328166

Thank you ScottW. I have gigabit internet at home. Using 40MHz is not an option to me. I can achieve 600Mbps+ download speed if I don't have any other device interference with me. Currently all my neighbors are on the lower frequencies of 5G channel, so I'm on the highest channel. Therefore even I use 80Hz I will have no neighbor bothering me. If I use 40Hz bandwidth, I get much lower throughput from my router. Currently, so far so good. I think the main step fixed my issue was turning off Universal Beamforming. I will keep an eye on this. Even I occasionally get signal drop once or twice a week. I'm still OK as trade off for higher speed. I will stay at 80MHz and wait and see if the issue comes back!

 

[webgrease]

I plan on flashing to 380.68_4 this weekend when I have some time and will change the suggested settings one at a time and will report back.

 

[AndreiV]

I plan on flashing to 380.68_4 this weekend when I have some time and will change the suggested settings one at a time and will report back.

I hope you don't waste any more time on 30/30/30 .... it doesn't exist in Asus/Merlin firmware.

 

[e38BimmerFN]

I had the 3100 for several days loaded with 380.68_x and never say any degradation in wireless signals. If your experiencing problems with one version than the other, you can always go back and use the prior version. You don't always need to have the latest.

Check your surroundings for wireless interferences as well.

I highly recommend not using the 30/30/30 reset process. Isn't not meant for ASUS routers and in general is a last ditch effort for those Mfr routers that use it. If you want a good clean way of installing FW, do a factory reset from the routers UI or the reset button. Use IE11 or FF browsers with no add-ons enabled and disable any PC security software temporarily. Send the FW file. Clear out the browser caches while the router is processing the FW update. Then do one more factory reset from the UI or the reset button then set up from scratch. This process has been working well for me for years.

For the most part Merlin FW doesn't need a factory set from scratch however maybe sometimes it would be needed going from a minor version of FW to a new major version so some differences could be seen and could cause problems unless a reset is performed and cleared out and set up from scratch. Avoid doing any 30/30/30 resets. Not needed here.

 

[webgrease]

I was up and running for a full week on Asus official RT-AC3100_3.0.0.4_382_15852 without a single issue, and I did not make any of the changes recommended above; all of the settings mentioned above remained at default. Today I flashed to 380.68_4, did NOT make the changes recommended above, and 5Ghz cut out in less than 2 hours. I just disabled Universal Beamforming, power cycled and will see what happens. If that doesn't work, I'll turn Universal Beamforming back on and will go down the list of recommendations one by one to find out which one resolves the issue. If none of them work individually, I'll start testing combinations until I find out which definitively works.

For those of you still hung up on me doing 30-30-30 as one of the steps in my process earlier, it's irrelevant. If you ignore 30-30-30, the first and last steps I described in the first post would sufficiently load the firmware and reset to factory default. At best for 30-30-30, the first 30 resets factory default, second 30 turns it off, last 30 puts it in recovery mode, which is when I'd reflash it with the Asus tool. At worst, it does nothing. Again, it's completely irrelevant to the main issue being discussed.

For this last flash, I used the GUI to load it, reset factory default, entered settings manually, powered off for a minute and powered back on. Still had the issue - again, irrelevant.

 

[DAVIZINHO]

hello.
Thanks for tell me this topic webgrease!
I have exactly the same problem like you. I have the ac88u but the problems are exactly the same.

I will wait for you test, if you find any solution i will test to confirm.
Now i not have any idea wich is the problem :-(

edit: now i just disabled Universal Beamforming and testing.....

 

[jumpycalm]

hello.
Thanks for tell me this topic webgrease!
I have exactly the same problem like you. I have the ac88u but the problems are exactly the same.

I will wait for you test, if you find any solution i will test to confirm.
Now i not have any idea wich is the problem :-(

edit: now i just disabled Universal Beamforming and testing.....

If you read my post above, you will know I have exact model as you and I have exact same issue. I applied change on 10/3/2017 and up until right now. I haven't seen the issue come back. Read my post for my steps resolved the issue. It's been 4 days without dropping any 5GHz signal. I can confirm my solution worked! The solution is actually very simple. It shouldn't take you more than 5 minutes.