Help with bricked RT-AC56U

[dzfacts]

I updated my router with the last update available on Admin GUI with no issues. After a few days I accidentally pulled the power adapter from power source and since then the router doenst show any signal of life, only its power led lights up, all Ethernet leds flash once power is on for a sec. I tried to put it on recover meode and set my windows laptop to some static IP (tried many 192.168.1.5, 1.10, 2.10) but the Asus utility fails (timeout) at finding it. I remember that it was set to a local IP of 192.168.2.1 because my fiber modem was set to 192.168.1.1, is it a problem? I think that the asus utility should be able to find it even if it was not set to .1.1 sub network.
I've been reading that it's possible to revive it using a Jtag cable but I'm not sure where to acquire one.
I'm desperately looking for some help to make it work again. Thanks

 

[dzfacts]

I've tried the reset with pin hole and also the wps trick, it just made the power led blink, when I release the wps button the router reboots indicated by ethernet leds flashing once and then it stuck again with the power led only, that's why I'm considering to use a jtag rescue, but not sure which cable to use.

 

[Hawk]

I've tried the reset with pin hole and also the wps trick, it just made the power led blink, when I release the wps button the router reboots indicated by ethernet leds flashing once and then it stuck again with the power led only, that's why I'm considering to use a jtag rescue, but not sure which cable to use.

Is power light blinking fast or slow?

 

[RMerlin]

What you need is a TTL serial cable, not a JTAG cable. JTAG is for when you trashed your bootloader - that is definitely not the case here since you can get the router into recovery mode (with the flashing power led).

Instead of using the recovery tool from Asus, just point your web browser at 192.168.2.1 (after you've put your computer on a 192.168.2.xyz IP, so the two can talk). There is a mini web server in the bootloader that lets you upload a firmware.

First, make sure the two devices can talk, by pinging the router on 192.168.2.1. A ping in recovery mode should return with a TTL of 100 instead of the usual TTL of 64.

Note that if you did a factory default reset, then you will have to use 192.168.1.x instead of 192.168.2.x.

 

[dzfacts]

Is power light blinking fast or slow?

Slowly

 

[dzfacts]

Im

What you need is a TTL serial cable, not a JTAG cable. JTAG is for when you trashed your bootloader - that is definitely not the case here since you can get the router into recovery mode (with the flashing power led).

Instead of using the recovery tool from Asus, just point your web browser at 192.168.2.1 (after you've put your computer on a 192.168.2.xyz IP, so the two can talk). There is a mini web server in the bootloader that lets you upload a firmware.

First, make sure the two devices can talk, by pinging the router on 192.168.2.1. A ping in recovery mode should return with a TTL of 100 instead of the usual TTL of 64.

Note that if you did a factory default reset, then you will have to use 192.168.1.x instead of 192.168.2.x.

I've tried both scenarios, 192.168.1.x and 192.168.2.x and both addresses doesn't return ping response and also there's nothing on the browser (192.168.x.1) after setting the IPs.
The power led blinks slow.

 

[Hawk]

Im


I've tried both scenarios, 192.168.1.x and 192.168.2.x and both addresses doesn't return ping response and also there's nothing on the browser (192.168.x.1) after setting the IPs.
The power led blinks slow.

Can you capture screenshot of computer showing what values you set ip address and other stuff

 

[dzfacts]

Im


I've tried both scenarios, 192.168.1.x and 192.168.2.x and both addresses doesn't return ping response and also there's nothing on the browser (192.168.x.1) after setting the IPs.

Site

Can you capture screenshot of computer showing what values you set ip address and other stuff

Sure, I'm not in home yet but once I get there I'll picture everything and post in reply. Besides, don't you think the serial and putty trick can fix it?

 

[dzfacts]

 

[Hawk]

Aha, I see your problem, no wonder ping is failing and webpage doesn't load. You need to put gateway address which is router address. Refer to my screenshot for help.
Once done follow Merlin Instructions, from "First, make sure the two devices can talk..."

http://www.snbforums.com/threads/help-with-bricked-rt-ac56u.31384/#post-248920

Make sure you use correct address by default Asus use 192.168.1.x range

 

[dzfacts]

Aha, I see your problem, no wonder ping is failing and webpage doesn't load. You need to put gateway address which is router address. Refer to my screenshot for help.
Once done follow Merlin Instructions, from "First, make sure the two devices can talk..."

http://www.snbforums.com/threads/help-with-bricked-rt-ac56u.31384/#post-248920

Make sure you use correct address by default Asus use 192.168.1.x range

Dude, it doesn't make any difference with or without the gateway, the router manual doesn't even point the need to set a gateway, anyway I did set it but still no signal, nor ping response.

 

[Hawk]

Dude, it doesn't make any difference with or without the gateway, the router manual doesn't even point the need to set a gateway, anyway I did set it but still no signal, nor ping response.

did you try with with bot 192.168.2.1 and 192.168.1.1 set in default gateway?

 

[RMerlin]

You don't need (and in fact you shouldn't put one) a gateway. Gateways are only used to route traffic intended to a different subnet (for instance, Internet traffic). You just need to se tthe IP and the subnet mask in this case.

The RT-AC56U has a quirky CFE, for some reason. Many times, I've gotten mine into a state where the CFE was failing to initialize the Ethernet interface, preventing it from being reachable in recovery mode. The fix is simple enough if you have access to a TTL serial adapter thankfully.

It's possible this is what is currently affecting it.

Just in case it's a defective network port, try to plug your computer into a different port.

 

[Hawk]

You don't need (and in fact you shouldn't put one) a gateway. Gateways are only used to route traffic intended to a different subnet (for instance, Internet traffic). You just need to se tthe IP and the subnet mask in this case.

The RT-AC56U has a quirky CFE, for some reason. Many times, I've gotten mine into a state where the CFE was failing to initialize the Ethernet interface, preventing it from being reachable in recovery mode. The fix is simple enough if you have access to a TTL serial adapter thankfully.

It's possible this is what is currently affecting it.

Just in case it's a defective network port, try to plug your computer into a different port.

Oh, I learned something new. Thanks Eric

 

[dzfacts]

You don't need (and in fact you shouldn't put one) a gateway. Gateways are only used to route traffic intended to a different subnet (for instance, Internet traffic). You just need to se tthe IP and the subnet mask in this case.

The RT-AC56U has a quirky CFE, for some reason. Many times, I've gotten mine into a state where the CFE was failing to initialize the Ethernet interface, preventing it from being reachable in recovery mode. The fix is simple enough if you have access to a TTL serial adapter thankfully.

It's possible this is what is currently affecting it.

Just in case it's a defective network port, try to plug your computer into a different port.

I'll check if changing the port might be a help, but I'm almost sure that it won't be because I've tried with a diferent eth port before, but not with all those different subnet scenarios. I'll check this today and give you the results.
By the way I've bought a serial adapter online last night, once it arrives all I need to do is a nvram reset or is it something else?

 

[dzfacts]

I just tested to put the router into "rescue" mode and noticed that only on the 1st and the 4th ethernet port it get its yellow led statically lighetd up while the green led blinks, unlikely the 2nd and the 3rd ethernet port only the green led light up (blinking, not static). I dunno what does it mean BUT on every IP config, 192.168.1.10 and 192.168.2.10, none of them the router responded to browser or ping commands. I'm not testing with the WAN connected just LAN.

 

[RMerlin]

I'll check if changing the port might be a help, but I'm almost sure that it won't be because I've tried with a diferent eth port before, but not with all those different subnet scenarios. I'll check this today and give you the results.
By the way I've bought a serial adapter online last night, once it arrives all I need to do is a nvram reset or is it something else?

Depends of what is the root problem. If it's the problem I've described related to the buggy bootloader, you have to "break" into the CFE prompt by keeping Ctrl-C during boot time. If however you are able to get into the CFE prompt normally by using the Reset button, then doing an "nvram erase" would be the first thing to try.

I know there's been a few guides posted on the forum on how to recover from CFE, some of them specifically targeting the RT-AC56U.

 

[dzfacts]

Depends of what is the root problem. If it's the problem I've described related to the buggy bootloader, you have to "break" into the CFE prompt by keeping Ctrl-C during boot time. If however you are able to get into the CFE prompt normally by using the Reset button, then doing an "nvram erase" would be the first thing to try.

I know there's been a few guides posted on the forum on how to recover from CFE, some of them specifically targeting the RT-AC56U.

I managed to get the USB to TTL and when accessing it via serial on putty, the command line fills with messed up characters at the speed 9600, but no response on 115200. Do You know how to fix it, I think the router might be accessible over cfe but there s something wrong with the set ups or with the TTL module.

 

[TonyH]

I managed to get the USB to TTL and when accessing it via serial on putty, the command line fills with messed up characters at the speed 9600, but no response on 115200. Do You know how to fix it, I think the router might be accessible over cfe but there s something wrong with the set ups or with the TTL module.

Try different Putty set up re: bits, parity, etc.

 

[RMerlin]

I managed to get the USB to TTL and when accessing it via serial on putty, the command line fills with messed up characters at the speed 9600, but no response on 115200. Do You know how to fix it, I think the router might be accessible over cfe but there s something wrong with the set ups or with the TTL module.

The correct settings are 115200, 8N1.

Make sure you connect GND, TX and RX. Do not connect VCC.

One way to test the serial adapter itself is to unplug it from the router, connect the TX and RX pin of the TTL adapter together, and make sure that what you type in Putty echoes back on screen.

Another gotcha which I have been unable to explain: some adapters will prevent the router from booting if you turn the router on while it's already hooked to the serial adapter. The workaround is to turn the router on without the adapter connected to the router, and immediately after turning it on connect the pin headers to your serial adapter.