Soft Reboot (fail) vs Hard Reboot

[drm200]

I have an Asus RT-AC86u running Merlin firmware 386.12.0. I normally do not need to reboot my router often … maybe every 3 or 4 months.

I was going to travel for 2 months, so I decided as a precaution to enable the Merlin boot rescheduler to reboot twice per week while I was gone. I verified the reboot was working before I left.

After about 3 weeks of travelling, I noticed my router was down as I could not access my smart thermostat, irobots, doorbell cam or video cams. So I waited for the reboots. But the reboots never brought any of the devices back online. I eventually returned 5 weeks later (during this time the router should have been rebooted 9 times by the reboot rescheduler) to find the router was on but erratic. I pulled the ac power and did a hard reboot. The router booted up normally, and everything came back online. I have had no issues since (about 2 weeks now).

My question is this: What is different between a soft (scheduled) reboot vs a hard (power down) reboot? What could have caused the router to fail to properly run after a soft reboot?

 

[Tech9]

This specific router model doesn’t soft reboot reliably. I have played a lot with different firmware versions and sometimes it just hangs on reboot. It happens randomly. The cause was never found. You can find it mentioned in other threads here on SNB Forums. Best course of action - plan a replacement. The router is facing End-Of-Life and has many known hardware and software issues.

 

[L&LD]

What caused the router/network to fail was to do unnecessary, automatic, scheduled reboots.

 

[drm200]

What caused the router/network to fail was to do unnecessary, automatic, scheduled reboots.

It is a devils choice. The router infrequently fails if not rebooted. Maybe twice per year. That is not a problem if I am home. But it is a significant problem if i am away. So while away, i configure the reboot scheduler. In my case, I consider it necessary in order to assure the router will continue to function while away

 

[Tech9]

The router infrequently fails if not rebooted.

The reason it fails is perhaps never resolved software bug on this model. It was discussed here:

Stuck commands

Has anyone else observed any "stuck" commands on their router since upgrading to 386.x? Below is a frequent occurrence of the wl command getting stuck being spawned by conn_diag (this process was created at 4:10 AM). But I've also seen it happen with some nvram get commands (I once had Skynet...

www.snbforums.com

When it happens is unpredictable. It may work for a year with no issues or fail twice in a week period.

 

[drm200]

This specific router model doesn’t soft reboot reliably. I have played a lot with different firmware versions and sometimes it just hangs on reboot. It happens randomly. The cause was never found. You can find it mentioned in other threads here on SNB Forums. Best course of action - plan a replacement. The router is facing End-Of-Life and has many known hardware and software issues.

The reason it fails is perhaps never resolved software bug on this model. It was discussed here:

Stuck commands

Has anyone else observed any "stuck" commands on their router since upgrading to 386.x? Below is a frequent occurrence of the wl command getting stuck being spawned by conn_diag (this process was created at 4:10 AM). But I've also seen it happen with some nvram get commands (I once had Skynet...

www.snbforums.com

When it happens is unpredictable. It may work for a year with no issues or fail twice in a week period.

Would you consider the rt-ax86u pro to have fewer issues?

 

[drm200]

The reason it fails is perhaps never resolved software bug on this model. It was discussed here:

Stuck commands

Has anyone else observed any "stuck" commands on their router since upgrading to 386.x? Below is a frequent occurrence of the wl command getting stuck being spawned by conn_diag (this process was created at 4:10 AM). But I've also seen it happen with some nvram get commands (I once had Skynet...

www.snbforums.com

When it happens is unpredictable. It may work for a year with no issues or fail twice in a week period.

Would you consider the rt-ax86u pro to not have this problem and be more reliable?

 

[Tech9]

Every model has own quirks. This is something ongoing with RT-AX86U Pro:

2.4ghz and 5ghz clients cant communicate with each other

Hi all, Apologies if this was addressed in another thread, I've been trying the forum search and didn't really find anything applicable. I have an Asus RT-AX86U Pro running 3004.388.4. I've configured 2 SSIDs a 5ghz one with SSID names formatted like this: WIFI_5G and WIFI. Both SSIDs use the...

www.snbforums.com

Not sure how many users are affected by this issue and when it will be fixed.

 

[bibikalka]

The reason it fails is perhaps never resolved software bug on this model. It was discussed here:

Stuck commands

Has anyone else observed any "stuck" commands on their router since upgrading to 386.x? Below is a frequent occurrence of the wl command getting stuck being spawned by conn_diag (this process was created at 4:10 AM). But I've also seen it happen with some nvram get commands (I once had Skynet...

www.snbforums.com

When it happens is unpredictable. It may work for a year with no issues or fail twice in a week period.

There is a partial remediation described here:

The RT-AC86U has a known problem with nvram access. It is described in this thread. The issue is exacerbated by running certain custom add-on scripts that make frequent nvram calls.

The issue can be reduced to some extent by adding the following line to the beginning of the /jffs/scripts/init-start script.

#!/bin/sh
echo 4194304 > /proc/sys/kernel/pid_max

It does not fix everything, but seems to help.

 

[Tech9]

This specific RT-AC86U model has multiple common issues and is facing End-Of-Life. The best course of action is replacement.

 

[bibikalka]

This specific RT-AC86U model has multiple common issues and is facing End-Of-Life. The best course of action is replacement.

Or - some brave sole would port 388 to RT-AC86U ! The cpu is the same, a few tweaks to the radio modules, and the router is as good as new again

 

[Tech9]

Not a solution. Most of the common issues with this model are hardware related.

 

[ColinTaylor]

There is a partial remediation described here:



It does not fix everything, but seems to help.

Your quote is missing some crucial text:

#!/bin/sh
echo 4194304 > /proc/sys/kernel/pid_max

 

[bibikalka]

Not a solution. Most of the common issues with this model are hardware related.

Well, a few issues were discovered after AC86u went out of favor with Asus. It's possible that the AX branch got updates, and those fixes are in 388 branch. Lots of AX routers look like AC86u cpu-wise, but with different radio chips. The wired network switch is the cpu itself, so those are the same in routers such as AX86s:

ASUS RT-AC86U - TechInfoDepot

"RT-AC86U REV 1.40" and "1650" is silkscreened on the board.

techinfodepot.shoutwiki.com

It might be that a slightly tweaked 388 would boot straight away on AC86u, with non-working radio chips. Radios would need more work of course.

Edit: It's interesting that Asus lists wired ports as identical for both AC86u and AX86s, the only difference appears to be 12V voltage option available as well, I guess they switched to a fancier voltage regulator:
RT-AX86S : 12 V with max.3 A current / 19.5 V with max. 2.31 A current

Your quote is missing some crucial text:

#!/bin/sh
echo 4194304 > /proc/sys/kernel/pid_max

Good catch! Not sure how that happened! I updated it.

 

[Tech9]

I guess they switched to a fancier voltage regulator

The same voltage regulators. Nothing inside uses 19V or 12V. All step-down VRMs and the router will work fine with either power supply.

 

[drm200]

Every model has own quirks. This is something ongoing with RT-AX86U Pro:

2.4ghz and 5ghz clients cant communicate with each other

Hi all, Apologies if this was addressed in another thread, I've been trying the forum search and didn't really find anything applicable. I have an Asus RT-AX86U Pro running 3004.388.4. I've configured 2 SSIDs a 5ghz one with SSID names formatted like this: WIFI_5G and WIFI. Both SSIDs use the...

www.snbforums.com

Not sure how many users are affected by this issue and when it will be fixed.

Thanks, This is the problem with replacing my current router .. It seems when you decide to upgrade you often are just replacing one problem for another. It is very difficult to find a router without some deficiency.

I have never had a problem after doing a hard reboot with my current router. It would be trivial for me to add a device that would occasionally do a hard reboot when I am traveling.

 

[Tech9]

It seems when you decide to upgrade you often are just replacing one problem for another.

True, but you have better chances to get a fix on a newer device with expected longer support.

 

[bibikalka]

True, but you have better chances to get a fix on a newer device with expected longer support.

Thanks, This is the problem with replacing my current router .. It seems when you decide to upgrade you often are just replacing one problem for another. It is very difficult to find a router without some deficiency.

I have never had a problem after doing a hard reboot with my current router. It would be trivial for me to add a device that would occasionally do a hard reboot when I am traveling.

Yeah, I am thinking the same - sometimes the devil you know is better than the one you don't The issue is that Merlin software is uncovering issues that Asus is not always willing to fix because they barely occur with stock firmware. Thus chasing upgrades my be counterproductive. AC86U was around forever, and still Asus did not fix all issues when all said and done. So what are the chances AX routers get their fixes before they become obsolete?

The same voltage regulators. Nothing inside uses 19V or 12V. All step-down VRMs and the router will work fine with either power supply.

So if I swap to 12V power supply, is that going to put less load on the VRMs? Or is it the same???