Hi,

couple of weeks ago, trying to roll back to default firmware on my OpenWRT installation I bricked my TL-WR841N v8.2 router. I don't know what I did wrong, but after unsuccessfull use of mtd I couldn't do anything (any command would fail with an "memory error").
After some searching I decided to try out serial recovery, using this article as a guide:

https://forum.openwrt.org/viewtopic.php?id=33906

The router described here is a little different then mine (mine is 8.2 revision), but I figured out that things should be alike.

So, I had a Cisco serial - RJ45 cable, which I connected to router and my laptop, which had a serial port. Alhough the serial section on a router mainboard was placed differently than on my example, I'm pretty sure I got the cabling right. I used this article as a manual, Table A-5 to be exact:

http://www.cisco.com/en/US/docs/securit … #wp1006200
So, I connected cable like that:

RX - 3 pin
TX - 6 pin
GND - 4 pin (tried on 5 pin, without any result).

So, I used Putty to connect to router with baud rate 115200, data bits - 8, stop bits - 1, and parity with flow control - none, as I find out in forums and ... got an unreadable output. It was a section of unreadable symbols, repeating over and over again. I checked all the baud rates I could possibly find without any results. Also, I double checked cabling and made sure everything was as it supposed to be.
So, do anybody have any idea that my problem might be? I would appreciate any help, because I don't have any clue what to do. Any help would be awesome.

Thanks.

you MUST NOT USE a RS232 port without an adapter, and you should stop trying, you can permanently fry the serial line of your router if you throw in more than 3.3V!

RS232 can work with 12V!

read for example:

http://wiki.openwrt.org/toh/tp-link/tl-wr1043nd#serial

Thanks for you answer. I suppose I got it all wrong, but I don't use VCC pin, so how can I fry the serial line if I don't pass power through it? I use only RX (receive), TX (transfer) and GRD (ground) pins to connect to it.

There's another option eventually. I looked at home and found usb to serial adapter, something like that:

http://www.ebay.com/itm/USB-to-RS232-RS … 1e808e6282

Can I use it instead of usb - serial cable? I wouldn't like to wait a month to get a new cable on ebay (that's how long it gonna take to ship it to Lithuania ;D).

If that wouldn't work for some reason - maybe you have some tutorial which cable to buy and how to connect it to router?

Thanks again.

TX an RX line on standard RS232 have higher voltage than a TTL adapter. Buy a cheap adapter (you can find them for $2 on ebay).