ac86u seems to be stuck in boot loop after firmware update

[RonaldT555]

This happened also to my RT-AC86U. I have this model only for couple of months. Was using Merlin firmware from the first day (mainly due to the temperature sensor readings in admin portal - I aslo installed heat dissipation fans). During past weeks it was behaving unstable - WiFi sometimes was completely off. Few days back I noticed that authentication is failing for 2.4G or 5G WiFi. Yesterday I connected with ethernet cable to sort it out, admin portal login page appeared as usual, but after entering login credentials it took 1 minute to load the next page. The page was anyway not loaded completely, and it appears that session timeout occured. I rebooted the router, and then it went into reboot loop. Exactly as shown here:

Today I tried with ASUS Firmware Restoration utility. It didnt worked for the first time - I was getting message in 30 sec that router is not found. But after 2-3 attempts finally it started to upload the firmware and now I have my router working again. Btw, keeping all my settings (so it was not doing factory reset). This time I flashed with original ASUS firmware, not Merlin. I want to monitor if strange things will start to occur again, this time with original firmware. I also logged a support request for ASUS to look at my System log, if they can find any problems there.

I did firmware reset following instructions given here: https://www.asus.com/support/FAQ/1000814
In short, it is following:

1. Download Firmware Restoration Utility and the firmware itself from this page: https://www.asus.com/Networking/RT-AC86U/HelpDesk_Download/

NOTE: Do not pay attention that Utility is for RT-AC66U!

2. Install Firmware Restoration Utility

3. Unzip firmware from zip file (will have filename *ubi.w)

4. IMPORTANT! Disconnect any other router or WiFi from the workstation (otherwise other router may block 192.168.1.* and mess up firmware restoration)

5. Go to Start -> Run -> ncpa.cpl

Open Local Area Connection and configure Internet Protocol Version 4 (TCP/IPv4) to following:

IP Address: 192.168.1.10
Subnet mask: 255.255.255.0
Default gateway: (empty)
Do not touch DNS servers (leave empty)​

6. Connect ethernet cable to RT-AC86U port No.4 (this is what worked for me) and the other end to the workstation

7. With router turned ON:
- press and hold down RESET button for 5 sec
- continue holding down RESET button, and power off (release POWER button)
- wait 5 sec
- continue holding down RESET button, and power on
- wait 5 sec
- release RESET button
=> Power LED will flash slowly - indicating that the router is in Rescue Mode
(Maybe it is possible in a shorter way, but, again, this is how it worked for me)

NOTE! Do not try to ping the router (it didnt worked for me) and do not pay attention to the Network Connectivity status.

8. Open Firmware Restoration Utility, Browse for the firmware (*ubi.w), and click Upload
NOTE: It may warn that firmware is not recognized as ASUS firmware..., just click Yes to continue.

9. Once you see that firmware have been uploaded, and router rebooted, there will be all the usual LEDs flashing and 2.4G and 5G WiFi appearing available under Network Connectivity icon. Disconnect the network cable and close Firmware Restoration Utility.

I was using Merlin firmware RT-AC86U_384.7_2_cferom_ubi.w, now I flashed with RT-AC86U_3.0.0.4_384_45149-g467037b_cferom_ubi.w.

Hope this will be helpful to anyone! Cheers!

 

[st3v3n]

Ronald, Thanks for a great outline. The boot loop routine is what we went through with two new 86s before adapting the upgrade method we used for the third replacement. The 86 is unlike every other Asus model we've owned, especially with the hidden FW. The time spent working on the first two units helped adapt the method we now use to upgrade, which takes about 30 minutes. We haven't needed the firmware restoration utility, not that it helped the two we returned.

We haven't used original Asus FW, so don't connect the new router to the internet until the upgrade is finished. We learned to keep the antennas off until the process is finished, and use a fresh browser session for each login. The returned units may have latched onto a neighbor's open WiFi and connected to Asus; it doesn't hurt to leave the antenna off, and since then each new upgrade has been trouble-free. On first-time power-up, we loaded and applied Merlin, logged out and removed power for a few minutes. Reapplied power/rebooted while watching the panel lights; the first time after applying the upgrade took several minutes longer than subsequent cycles.

The next cycle we changed ID/PW and then the IP address to what we've always used, 192.168.1.1. Also adjusted the network range as outlined in the wiki. Logged out, removed power and waited a few more minutes. Reapplied power/rebooted , then went completely through the GUI, setting up WiFi and installing the OPVN configs, then logged out and removed power a final time. Installed the antennas, connected Ethernet between the main computer and router and between WAN and modem; reapplied power/rebooted, then completed the setup. The router has run well every since.

Other folks also have written about similar problems with their new 86s, that resisted upgrading to Merlin, or seemed to revert to the hidden FW. YMMV; not everyone will choose the same way. Hope this helps, good luck.

 

[ml70]

Btw if you have trouble with Asus firmware restoration utility, just use tftp it's available on Linux and Windows (install from Control Panel>Programs and Features>Turn Windows features on or off>TFTP Client).

This does it all

tftp -i 192.168.1.1 PUT WhateverFirmware.trx

Remember to let it through your firewall.

There's a timeout window with uploading it (at least on my AC66) so have the command line ready when your router enters recovery mode.
But this does it when Asus FRU won't.

 

[OMNI619]

I experienced the same issue I use the mini web server I let it for two hour and after that everything was good sometimes you get failed upload firmware router still in recovery mod

Sent from my SAMSUNG-SM-G920AZ using Tapatalk

 

[emikaadeo]

This happened also to my RT-AC86U. I have this model only for couple of months. Was using Merlin firmware from the first day (mainly due to the temperature sensor readings in admin portal - I aslo installed heat dissipation fans). During past weeks it was behaving unstable - WiFi sometimes was completely off. Few days back I noticed that authentication is failing for 2.4G or 5G WiFi. Yesterday I connected with ethernet cable to sort it out, admin portal login page appeared as usual, but after entering login credentials it took 1 minute to load the next page. The page was anyway not loaded completely, and it appears that session timeout occured. I rebooted the router, and then it went into reboot loop. Exactly as shown here:

Today I tried with ASUS Firmware Restoration utility. It didnt worked for the first time - I was getting message in 30 sec that router is not found. But after 2-3 attempts finally it started to upload the firmware and now I have my router working again. Btw, keeping all my settings (so it was not doing factory reset). This time I flashed with original ASUS firmware, not Merlin. I want to monitor if strange things will start to occur again, this time with original firmware. I also logged a support request for ASUS to look at my System log, if they can find any problems there.

I did firmware reset following instructions given here: https://www.asus.com/support/FAQ/1000814
In short, it is following:

1. Download Firmware Restoration Utility and the firmware itself from this page: https://www.asus.com/Networking/RT-AC86U/HelpDesk_Download/

NOTE: Do not pay attention that Utility is for RT-AC66U!

2. Install Firmware Restoration Utility

3. Unzip firmware from zip file (will have filename *ubi.w)

4. IMPORTANT! Disconnect any other router or WiFi from the workstation (otherwise other router may block 192.168.1.* and mess up firmware restoration)

5. Go to Start -> Run -> ncpa.cpl

Open Local Area Connection and configure Internet Protocol Version 4 (TCP/IPv4) to following:

IP Address: 192.168.1.10
Subnet mask: 255.255.255.0
Default gateway: (empty)
Do not touch DNS servers (leave empty)​

6. Connect ethernet cable to RT-AC86U port No.4 (this is what worked for me) and the other end to the workstation

7. With router turned ON:
- press and hold down RESET button for 5 sec
- continue holding down RESET button, and power off (release POWER button)
- wait 5 sec
- continue holding down RESET button, and power on
- wait 5 sec
- release RESET button
=> Power LED will flash slowly - indicating that the router is in Rescue Mode
(Maybe it is possible in a shorter way, but, again, this is how it worked for me)

NOTE! Do not try to ping the router (it didnt worked for me) and do not pay attention to the Network Connectivity status.

8. Open Firmware Restoration Utility, Browse for the firmware (*ubi.w), and click Upload
NOTE: It may warn that firmware is not recognized as ASUS firmware..., just click Yes to continue.

9. Once you see that firmware have been uploaded, and router rebooted, there will be all the usual LEDs flashing and 2.4G and 5G WiFi appearing available under Network Connectivity icon. Disconnect the network cable and close Firmware Restoration Utility.

I was using Merlin firmware RT-AC86U_384.7_2_cferom_ubi.w, now I flashed with RT-AC86U_3.0.0.4_384_45149-g467037b_cferom_ubi.w.

Hope this will be helpful to anyone! Cheers!

Hallo and welcome.
I got exactly the same issue.
I follow your steps precisely. Firmware have been uploaded successfully.
Router reboots but it is still in loop.

Have you guys got any more ideas?
I can't do RMA so I really want to make this router works again.

 

[bombay63]

Same issue with RT86U from Amazon warehouse. Upgraded Asus firmware to latest Merlin 384.8_2. Did a reboot and it worked fine. Once I did a power on off, boot loop started. Not going to bother with recovering image, just will send it back to Amazon.

 

[Deleted member 28123]

Same issue with RT86U from Amazon warehouse. Upgraded Asus firmware to latest Merlin 384.8_2. Did a reboot and it worked fine. Once I did a power on off, boot loop started. Not going to bother with recovering image, just will send it back to Amazon.

Bought mine from Amazon too but did not have this issue. I read somewhere in the forum that flashing it twice was recommended which I did - flash then clear nvram then flash again then reboot.

If yours still bootloops after this then it's probably a bad memory chip.

 

[Grisu]

We learned to keep the antennas off until the process is finished, and use a fresh browser session for each login.
it doesn't hurt to leave the antenna off, and since then each new upgrade has been trouble-free.

It shouldn't hurt but it can hurt Wifi-chips if they operate in open output circuit.
I wont do this, turn off Wifi with button instead if possible or somewhere with no other WiFi networks or put it into a metall box (foil).

 

[emikaadeo]

Hallo and welcome.
I got exactly the same issue.
I follow your steps precisely. Firmware have been uploaded successfully.
Router reboots but it is still in loop.

Have you guys got any more ideas?
I can't do RMA so I really want to make this router works again.

A little update.
I've managed to unloop this router (3 times)
Every time I needed to clear nvram and after that completely disconnect it from power source for at least a couple of hours.
But then, every time I'm trying to change my Region (through GUI) from China to Europe (my SKU is from China) it starts to write settings, then reboot and bootloop is back.
I'm using ASUS firmware version 3.0.0.4.384.45149

 

[st3v3n]

Grisu, I didn't write some things up. but during the first logon with the 3rd unit upgrade, the radios were turned off prior to loading the upgrade, for what it's worth. I could've mounted the antennas and slipped EM resistant material (or a jacket as I call it) around them. We'd performed work on other routers with the antennas unmounted, with no issues. For all others, YMMV. This was as low-risk as it could be made. Worked on electronics since the 60's when many electronic units were prone to abrupt, spectacular, smoking failure if a no-load condition was present (or as Elon Musk describes, RUD; rapid, unscheduled disassembly). The first two routers were disappointments but the 3rd is great and worth the effort expended. The day of the upgrade, the neighbor's EM power levels were reduced; we didn't expect problems, but the fellow pumps out scads more energy than anyone would consider healthy.

The work area is below ground-level, and the building is as EM resistant as we could build it. Leaving the antennas off was a judgment call. If anyone else leaves their antennas off, be aware it's not a documented service technique; it's your unit and your call. We're mindful of excessive transmission power levels because of our local problem, not dissimilar to what existed in the 70s radio craze. Our WiFi can be measured outside the front door using good equipment, so good planning pays off. Booster amps now as in the old days with radio, created severe disruption. When the FCC ignored consumer complaints, some resorted to destroying offending radio towers and installations, which were usually running again within days. With today's modern gear, WiFi/mesh tech, lower EM levels are better. Cheers.

Emikaadeo, Not sure on this one, but if your router is meant for china's region, you'll likely be disappointed trying to keep it 'stuck' in the EU region (Bit of a jest, as the UK is having similar issues

 

[Bong Li]

Grisu, I didn't write some things up. but during the first logon with the 3rd unit upgrade, the radios were turned off prior to loading the upgrade, for what it's worth. I could've mounted the antennas and slipped EM resistant material (or a jacket as I call it) around them. We'd performed work on other routers with the antennas unmounted, with no issues. For all others, YMMV. This was as low-risk as it could be made. Worked on electronics since the 60's when many electronic units were prone to abrupt, spectacular, smoking failure if a no-load condition was present (or as Elon Musk describes, RUD; rapid, unscheduled disassembly). The first two routers were disappointments but the 3rd is great and worth the effort expended. The day of the upgrade, the neighbor's EM power levels were reduced; we didn't expect problems, but the fellow pumps out scads more energy than anyone would consider healthy.

The work area is below ground-level, and the building is as EM resistant as we could build it. Leaving the antennas off was a judgment call. If anyone else leaves their antennas off, be aware it's not a documented service technique; it's your unit and your call. We're mindful of excessive transmission power levels because of our local problem, not dissimilar to what existed in the 70s radio craze. Our WiFi can be measured outside the front door using good equipment, so good planning pays off. Booster amps now as in the old days with radio, created severe disruption. When the FCC ignored consumer complaints, some resorted to destroying offending radio towers and installations, which were usually running again within days. With today's modern gear, WiFi/mesh tech, lower EM levels are better. Cheers.

Emikaadeo, Not sure on this one, but if your router is meant for china's region, you'll likely be disappointed trying to keep it 'stuck' in the EU region (Bit of a jest, as the UK is having similar issues

Hello, thanks very much for the sharing!

I have an ac86u and I think I’m undergoing similar problems and your sharing has shed light on me.

My ac86u suddenly went into bootloop one day (without any upgrading of the firmware). I have always been using official firmware from asus.

After restoring stock firmware, with the antenna unmounted the router is able to boot up with wifi on. But with antenna mounted it doesn’t boot up.

The advice I would like to seek from you is that, since I would like to use stock firmware for aimesh, how I should proceed with the settings? Will simply changing the user id and password make the ac86u behave normal with antenna attached?

 

[RonaldT555]

In my case, one network band disappeared completely and there were seldom some problems (eg, kicking out from user session when accessing System Logs page on router web portal, also some other problems now don't remember what it was...). This time I did reboot a few times, but didn't tried to fix it myself (no factory reset, etc), just brought it back to the shop and they did diagnostics with their supplier. Identified that item is faulty and I got completely new replacement unit in a matter of a few days! It was important that there was latest original firmware on the router, otherwise they said they would not take it for testing! I went through initial setup, upgraded (original) firmware (btw, I left antennas on during this process (sorry st3v3n)), and the router is working without restart already for one month. I have not done any configuration changes from the defaults.

I think I will leave original firmware for a few months now, to see that everything works. Then will try to put Merlin once again. Need to do this while in warranty period .

 

[st3v3n]

Bong Li, Since we don't use the official FW since we don't use AiMesh, as close as you can get to stock and new, the better. Using the official/latest Asus restoration tool, without any connection to the internet should zero the router out, to where it thinks it's a factory fresh unit. It should have the usual stock login and PW. If you log off after the restoration and disconnect the power, then wait several minutes prior to plugging the power to the router in again, then letting it take whatever time it needs to come up, it should allow you to log in with that generic ID/PW If not, then hopefully some old hands with the official FW can help, or you might try submitting a ticket with Asus, since it's stock. Hope this helps.

 

[Anezle]

All of a sudden my Ac86u bricked itself. I was surfing the internet (so, no intense task) when it happened. At first I thought about a downtime from my ISP.
When I looked at the router lights situation and impossibility to access to its gateway, it was clear it was bricked all of a sudden.

I tried to put it in rescue mode (both WPS and RESET procedures) but nothing worked.
It stays with 1 light fixed (the power one). And it is not detected by my PC if connected with Ethernet (LAN1). What else can I do ?
I have been using Asus Merlin on it since the very first day (January 2018), since it's great to maximize Aes-Ni performance of this unit. I never ever had any problem so far.

Please help me, I love this router.

 

[L&LD]

Unplug all cables, including any USB devices and power too (from both the AC wall outlet and the power plug on the router).

Wait for at least 2 minutes.

Power it up.

If this doesn't work, you may need a new power adaptor (they do fail sometimes).

HTH.

 

[Anezle]

Unplug all cables, including any USB devices and power too (from both the AC wall outlet and the power plug on the router).

Wait for at least 2 minutes.

Power it up.

If this doesn't work, you may need a new power adaptor (they do fail sometimes).

HTH.

Thank you.
I am playing my chances by ordering a new power adapter (model ADP-33AW) for 12$ on Aliexpress. Meanwhile I get back using my ISP router.