How do I completely wipe my RT-AC66U?

[unknown14725]

I'm experiencing some issues with SNMP, and it also seems like rebooting my unit takes a very long time now, with the occational need to actually reset it to get a proper boot once in a while. When router has booted, the CPU is at 100% sometimes, and memory use skyrockets instantly to 73% and remains there.
It started a few days ago after installing the Asus Download Master and installing and a couple of harmless ipkg packages such as nano and mc. At least that's what I think did it.



I've tried resetting to factory defaults, but the problem is still there. I've also tried re-flashing 378.53_0. Didn't help.

I cannot get into recovery mode (holding reset button while powering on). The power led starts blinking slowly, but 192.168.1.1 doesnt respond. (I've set my own IP to 192.168.1.50).

If I telnet in to my unit, the ipkg packages I've installed are still there, so it's pretty clear resetting to factory defaults does nothing to the contents of the internal storage. Is there some way to "format" the device, so all data is removed? So I can get a new fresh internal storage, just like it comes from the factory?

I've tried googling quite a bit, but I dont really know what to search for tbh. All results just deal with resetting the settings.

 

[Deleted member 22229]

Did you try resetting via the WPS method ? Turn router off then power the router on while holding down the WPS button continue to hold for about 10 to 15 seconds then release and allow router to boot. If this method don't put you back to factory default you have something else going on there.

 

[unknown14725]

Reset settings by holding WPS button does not help either.

 

[unknown14725]

Update: I tried ejecting the 16GB USB drive I had connected, and cpu sage and ram went back to normal. Could it be something in Asus Download Master that was borked? Even though it was uninstalled/disabled the program files were still on it.

I dont know enough about how this works unfortunately. Does it automatically run/mount stuff on the USB drive simply because it's connected? How does this work?


Update 2: ejecting and formatting the flash drive has fixed the issues with cpu load and mem use.

But I am still having a lot of problems with SNMP, and a lot of information is suddenly not available. Things like cpu usage and number of processes running are not available anymore.


Update 3: after googling a bit on SNMP I found out that I could re-install net-snmp:

ipkg install net-snmp

...and this fixed my issues with SNMP. I am still unsure if there are other hidden problems that will appear later. Sigh, getting a bit paranoid here... This did not help, and after a reboot i'm back to snmp not working fully

Update 4: rebooted, and snmp problems are still there

So the request on how to wipe the device completely still stands.

 

[RMerlin]

Go to Administration -> System, select the option to reformat the JFFS partition, then reboot. That will erase the JFFS partition content.

After that, press the reset button for about 5 seconds, and let the router reboot. That will take care of nvram.

 

[unknown14725]

Hi there

yeah, I've already tried formatting JFFS and rebooting. Also did the reset button a few times today.

didnt help

I'm suspecting some of the software (binaries?) or their configurations have been modified somehow.

Exactly what does a firmware upgrade do? Does it format the internal storage ("system disk")? Or does it simply overwrite current files and directories with new ones? Not a linux expert, so the terminology is not too strong with me yet. I'm still seeing things there from a previous firmware. For example I see a directory /opt in the root that doesn't work anymore (a symbolic link?) And the /tmp directory is full of stuff.

 

[RMerlin]

Hi there

yeah, I've already tried formatting JFFS and rebooting. Also did the reset button a few times today.

didnt help

There's nothing else for you to erase. These are the two only writable location in the router.

I'm suspecting some of the software (binaries?) or their configurations have been modified somehow.

Exactly what does a firmware upgrade do? Does it format the internal storage ("system disk")? Or does it simply overwrite current files and directories with new ones? Not a linux expert, so the terminology is not too strong with me yet. I'm still seeing things there from a previous firmware. For example I see a directory /opt in the root that doesn't work anymore (a symbolic link?) And the /tmp directory is full of stuff.

The upgrade overwrites the entire rootfs partition. That partition is read-only, so its content cannot be modified, beside by overwriting the whole partition with an image.

/tmp is in RAM, it uses tmpfs.

 

[unknown14725]

Ok, nice to have these things clarified.

So, when I install stuff like mc or nano using ipkg it gets physically installed to JFFS? And a format of JFFS means it's gone. But there could still be things in nvram pointing to stuff on JFFS, I guess, and that could be causing problems. Might have another go at resetting and formatting, just making sure I do in in proper order now.

The directory structure of this device is very confusing for me (I'm a Windows guy), but I also now realize is very clever, because this means it uses flash memory (JFFS) for some dierctories and parts of the OS that requires writing, while the rest is read-only?

 

[RMerlin]

Ok, nice to have these things clarified.

So, when I install stuff like mc or nano using ipkg it gets physically installed to JFFS?

No. Optware/Entware packages are installed on the USB disk. The JFFS partition will only contain scripts to automatically stop/start the Entware services, and any other customization you might have put there.

The directory structure of this device is very confusing for me (I'm a Windows guy), but I also now realize is very clever, because this means it uses flash memory (JFFS) for some dierctories and parts of the OS that requires writing, while the rest is read-only?

It's a typical Linux filesystem. You should familiarize yourself with basic Linux FS concepts, such as mount points - that alone will explain a lot of things once you've understand them, as it's a concept that's very rarely used under Windows, but a vital part of how Linux filesystems work. In summary: there is a root (/), and EVERYTHING is under the root. All filesystems are mounted somewhere within that root.

 

[unknown14725]

I just wanted to inform that I've managed to get my things sorted out here. I did not realize that JFFS and NVRAM were separated, and that ipkg stuff got installed to the USB flash drive. Again, thanks for explaining.And yes, mounts are not used much in Windows. The closes I've come is using junctions a few times.

However, I did come across a sort of discrepancy in regards of SNMP.

If I install your firmware, and simply enable SNMP in the UI, there are some OID that provide incorrect - or no values at all. Example from the top of head is number of processes (hrSystemProcesses). I also suspect that hrSystemUptime is showing number of days in the current year instead of actual system uptime. At least that happened to me twice the last week.

I've found out that doing a "ipkg install net-snmp" and "app_set_enabled.sh net-snmp yes" fixes these things.
Could it be that the version of snmp included in your firmware is a different/older version?

EDIT: words and screenshot from prtg to illustrate the discrepancies in snmp

The blue line shows uptime, and it went to 145 days when I reinstalled your firmware, and processes went to blank. It fixed itself when I installed net-snmp. I confirmed these values by using an external snmp browser (SnmpB)