Serial Flash - No Console Output

[netmind]

I'm trying to unbrick my RT-AC56U via serial flash.

I been able to connect the usb to serial cable and can get a terminal window up through Putty but it stays empty no matter what I do.

So as a test, I connected the cable to another Asus router that is working just to see if the boot output show up. No boot output either, although the router boots up just fine.

I can see the leds on the usb serial cable light up (although I have no idea what they mean).

- Serial cable - CP2102 USB to TTL cable , latest SiLabs drivers from here

- Putty - 115200 / data: 8 bit / stop: 1 bit / parity: none / flow: none

- COM port confirmed in windows device mgr

The boot output should just show up once I power on the router right (no ctrl + c needed)?

Am I doin something wrong? Are those the right putty configurations for the CP2102 chip?

 

[RMerlin]

Try swapping TX and RX.

 

[netmind]

Yup I tried swapping the tx and rx but no change.

Also tried connecting the vcc up as the dd-wrt instructions noted some boards may need it - no change either though.

Tried to log all session output but no log file created (although I confirmed a log will be created for simple SSH session). Also run putty as administrator, but no change.

 

[RMerlin]

I remember the RT-AC56U bootloader could be a fair bit quirky at times. Try plugging the serial pins only 3-4 secs after you powered the router on - I remember I had to do that for certain routers, but I can't remember which models.

 

[Darkje]

Yes like @RMerlin said. Turn on and then plug in the tx pin.

 

[netmind]

Not sure if the window is short for post power plug in but my fat fingers are quite slow at plugging in the jumpers .

Anyhow, I did a loopback test (plugged same wire back into the adapter, tx-rx) and couldn't see what I was typing in the console. So I guess I got a DOA adapter or I shorted it out.

I'll have to source a different usb serial adapter and come back to this.

Thanks for the suggestions and help.

 

[Darkje]

Not sure if the window is short for post power plug in but my fat fingers are quite slow at plugging in the jumpers .

Anyhow, I did a loopback test (plugged same wire back into the adapter, tx-rx) and couldn't see what I was typing in the console. So I guess I got a DOA adapter or I shorted it out.

I'll have to source a different usb serial adapter and come back to this.

Thanks for the suggestions and help.

Only one cable... Just get a simple switch in between.

 

[netmind]

Well I dug out my old CA-42 diy serial cable from 10 years ago and was able to get it to work with the the working RT-N66U. Boot output shows up fine in the console and I was able to ctrl+C break into the CFE prompt.

However, still can't get anything in the console with the RT-AC56U. I also tried to plug in cable 3-4 seconds after powering on the unit. Unfortunately no boot output showed up and ctrl+C had no effect.

Guess I really bricked it good. I guess time to put this unit in the bin.

Thanks though.