RT-AC86U upgrade to f/w 3004.386-46092 fails - panic...

[BosseSwede]

I have a number of ASUS routers on my different LAN:s and I have successfully upgraded each to the latest ASUS release f/w on all of them except my main router. I have used both the admin GUI (when I had downloaded the f/w file from Asus first) and the ASUS Router App on my phone, which can locate the latest f/w automagically.

I decided to update the main router today from 3004.384_32799 to 3004.386.46092 and used this procedure:
1) Use the web GUI Admin function to save current settings to a file
2) Use the ASUS Router app on my phone to update to 46092
3) After the 3 minutes wait it was supposed to be done, but now BIG PROBLEMS!

At the moment my wifi is visible but it does not hand out any IP address to a connection attempt, so it fails.
On the wired LAN I can ping the router 192.168.119.1 and get a response, I also can do that from a Linux machine connected by wire.
I can still connect by SSH to my other Linux machines on the LAN.

But I cannot log on to the router's GUI, nothing shows up when I browse to the router address.
Same with SSH, there is no connection to that address (refused).

I have tried to power cycle the router to no avail.

What can I do now?
I have googled on this issue but only found answers concerning the AsusWRT Merlin f/w, but I am using stock ASUS f/w.

 

[BosseSwede]

UPDATE:
By resetting the router to "factory settings" I could start it up and get access to its config page (of course now at 192.168.1.1).
So then I tried to reload the saved configuration file from before I updated the firmware - and again this bricked the router!

It seems like doing the f/w update from the version 3004.384_32799 to the most current 3004.386_48260 does indeed make the router unusable unless it is factory reset afterwards.
As does loading the saved settings on the factory reset router.

So I had to spend a lot of time (like 4-5 hours) manually replicating the old settings from scraps of notes I could find. Not so simple since this router handles a lot of devices on the LAN including VPN and SVN servers.

But I finally got it done.
Now running.

Advice:
Before doing this kind of upgrade, please walk through all of the config pages of the router before upgrade and take screenshots of them all.
Then you will have some help going forward.
I wish there would be a tool to decode the cfg settings file into clear text to be used while setting up anew.

 

[ColinTaylor]

It seems like doing the f/w update from the version 3004.384_32799 to the most current 3004.386_48260 does indeed make the router unusable unless it is factory reset afterwards.

Disappointing Asus didn't catch this, but not entirely surprising given that 384_32799 is almost 4 years old, 18 releases behind and a completely different code base (384 vs. 386). A cautious approach for such big changes is to update to the last 384 release first and then update to the current 386 release.

There is also a database migration process that runs after updating from 384 to 386. This can make the router's GUI inaccessible for up to an hour, although some users reported having to wait nearly 24 hours for it to complete!

As does loading the saved settings on the factory reset router.

A settings file from one firmware version should never be loaded into a different firmware version, that's not its intended purpose. In particular 384.81992 introduced security changes (e.g. encrypted passwords) which require a factory reset when trying to return to a release prior to this.

 

[BosseSwede]

I think I am OK now with manually configuring the stuff I had before the upgrade. Yesterday I found out that I had missed one route entry, which is needed in order to connect to an RPi device connecting by OpenVPN to my home LAN. It was not in my notes because it was pretty recently added.
But when I could not SSH to it I soon realized the lack of route and fixed it. I think everything now works as it should.
And also:
The router admin GUI is now able to check for new f/w upgrade availability. Did not work earlier.