RT-AX88U - Unable to update firmware

[Irish1986]

I am using an RT-AX88U with firmware 386.3 although I want to update to the latest. I am not certain where this is coming from but the GUI isn't as I was remembering. The upload button allows me to select a new firmware but it does not get loaded. It says "applying setting" for over 30 min and upon reboot the router was still at 386.3 instead of 386.3_2. Any suggestion ?

 

[L&LD]

Safely remove any USB devices attached to the router via the web GUI.

Physically remove them.

Reboot the router via the GUI menu.

Re-download the firmware, verify the hashes, double-check you downloaded the correct firmware file, then flash again.

After the router is at the firmware you want, insert the USB devices (if any). After 15 minutes or so (we are letting the router settle after the upgrade/reboot), reboot the router once more and double-check that everything continues to work properly.

 

[Zendilar]

I have the same problem but only when I try to remotely update the firmware, when I do the procedure locally it upgrades just fine.
This is happening for some time now (the last 3 or maybe 4 firmware versions I had to be on site to upgrade them),
in the past I use to upgrade the F/W remotely all the time with no problem.
I have used all the browsers that are out there, incognito, privet windows, disable firewalls in the routers and can't find a solution.

If someone can point my to the right setting that I can make to remotely update the firmware of my RT-AX88U I would be obliged.
Also the same thing is happening on my three DSL-AC68U that are running on Gnuton firmware, at first I thought that it was something related to his version of the Merlin+dsl modem F/W but after I bout the RT-AX88U and installed 386.3_0 the same thing happened when I try to remotely upgrade to 386.3_2 . (I had to go on site and locally do it)

For the record, all the devices have identical settings and no USBs attached so there is definitely some setting that is messing with the remote upgrade.

Any help would be appreciated

Thanks in advance.