DSL-AC88U Recovery Mode (Rescue Mode) and Clearing NVRAM Guide

[UK Sentinel]

Detailed below is the instructions from ASUS on how to put the DSL-AC88U into Recovery Mode (Rescue Mode) to enable the loading of firmware from outside of the Routers UI (User Interface) and also details (simple) on how to clear the DSL-AC88U NVRAM.

(Also works for DSL-AC3100 and DSL-AC88U Annex B)

Put the DSL-AC88U into recovery mode (it should be the “rescue mode”):
[On your Router]

1. First, unplug the power core (DC IN) of DSL-AC88U Router.

 

Next, long-press the button “RESTORE” about 5 seconds and plug in DC IN behind the DSL-AC88U Router.

The DSL-AC88U router is on rescue mode now (no LED’s blink but WiFi LEDS Glow Dull).

 

[On your Computer]

Connect with computer and DSL-AC88U Router as bellow picture – green line(LAN).

Click 「Start」→「Control panel」→ 「network and Internet」→「Network and Sharing Center」→「Change adapter settings」at left page

「LAN」→right click「properties」→click「Internet protocol version 4 (TCP/IPv4)」→click 「properties」at the bottom of page→modify the content as bellow

Use the following IP address，IP address：192.168.1.10， subnet mask：255.255.255.0  → click「OK」

You can update the firmware by entering the URL “192.168.1.1” via your browser:

 

If the update is successful, a message will appear stating the update will take about 2 minutes

2) How to erase the routers NVRAM?
Go to the Administration > Restore/Save/Upload Setting page, and press the “Restore” button of the “Factory Default” option.

Hope this Proves Usefull?

UK Sentinel

 

 

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[Andy]

Is the restore button the small red as in picture obtainable with cocktail stick.

if so when I hold this in and connect DC power the router doesn’t power up at all.

If I release it still doesn’t fire up until I hit the power button off and then on again.

It then just starts normally

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[UK Sentinel]

It is,  keep it pressed in for a good  5 seconds and plug in DC IN and WiFi LEDS should Glow Dull –  try it a few times just to make sure.

If that fails then it is not looking good

 

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[Andy]

UK Sentinel wrote:

It is, keep it pressed in for a good 5 seconds and plug in DC IN and WiFi LEDS should Glow Dull – try it a few times just to make sure. If that fails then it is not looking good

Don’t think it’s just me that hasn’t been able to do that reset. A large amount of googling only resulted a lot of users not able to get a DSL-AC88U to do this maybe it only works on RT-AC88U.

Anyone know the model number of the NVRAM chip so I can get a clean one ready before I open the box

 

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[UK Sentinel]

Are you not concerned that the firmware has not been updated for nearly 2 1/2 years from a security standpoint ?

 

 

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[Andy]

UK Sentinel wrote:

Are you not concerned that the firmware has not been updated for nearly 2 1/2 years from a security standpoint ?

Ofcourse but that was Asus decision to stop supporting firmware on this model which I paid £270 for in July 2017. Given that it’s not even 4yrs old doesn’t represent good value or faith in the brand.

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[UK Sentinel]

Agreed, but you still own that risk – Alas the DSL-AC88U used an non standard firmware from a code/language perspective – so  I am unable to have a look at my own DSL-AC88U to see what type of NVRAM is used.

 

 

 

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[Andy]

UK Sentinel wrote:

Agreed, but you still own that risk – Alas the DSL-AC88U used an non standard firmware from a code/language perspective – so I am unable to have a look at my own DSL-AC88U to see what type of NVRAM is used.

 

As always UK sentinel, thanks very much for your help but I wouldn’t want you to open your up just to take a look. A little more reading revealed the possibility of a nandflash issue which is very common within the equipment I repair so it could be an easy fix.

Is it possible to Telnet the dsl-88u to issue some commands?

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[UK Sentinel]

A possible nandflash fix sounds good and let us all know what you did as I am sure others would be interested also.

Alas by default, the DSL-AC88U did not support any form of Telnet /SSH access, but I have a debug firmware for the DSL-AC88U that I could send you a link if you wish ?

 

 

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[Andy]

Yeah, I would like to use the debugging firmware

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[UK Sentinel]

Andy wrote:

Yeah, I would like to use the debugging firmware

I have emailed you the link

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[Andy]

Thanks UK Sentinel,

Well after spending far to much time than it’s worth the unit is now retired to land fill.

Debugging firmware didn’t work so I opened up the box and the heat sink had lifted away from the PCB. Obviously heat damage to one of the components causing the problem.

Sometimes it’s just better to open up and take a look 👀

I will still be around the forums as given my VPN needs I cannot find an alternative to the RT-AC88U even though I’m disappointed with the short lifespan & support of the DSL-AC88U

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[UK Sentinel]

What about the DSL-AX82U ? and there is an ASUSWRT-Merlin build for it via @GNUton – GNUton

Maybe worth a look at when you have time

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