Sorry guy i researched a lot  , i found some info on this forum about same topic. but i don't have any clue about this.

I bricked my Modem ( TP-Link TL-MR3220 v2 ). It keeps flashing its all leds and i take it as bricked.

I want to Unbrick it. Please post some steps here ( Newbie Friendly  and easiest )  with as much as details as possible. Remember its Version 2! Also i want to go back to Original Firmware for TpLink.

My Technical Knowledge :

I am familiar with linux ( advance user ). But i don't know enough about Routers and Firmwares

Thanks in Advance.

(Last edited by nokiaberrygenius on 4 Jul 2013, 18:16)

I am thinking about getting this : http://www.ebay.in/itm/USB-To-RS232-TTL … 216wt_1139

Will it work with this Device?

Please let me know the easier way to do this.

Thanks!

(Last edited by nokiaberrygenius on 4 Jul 2013, 18:33)

No response? Where should i ask for help then?

Not sure about this router, nor is this answer specific for your router, but:

Often people (including myself) buy a Nokia DKU-5 (ca-42) cable
Cut off the one end, strip the wires, find out which is tx/rx/gnd and you're good to go

Also, carefully read the openwrt wiki on your router

It most often contains valuable information about unbricking and going back to stock

Thanks fo your constructive response. Still looking for more specific solution. That Cable will work for sure?

No the cable will not "work for sure". You will need to make a jumper cable as described in other topics on this exact topic. After that the cable will work. Read this and attempt to do the same yourself:
https://forum.openwrt.org/viewtopic.php?id=42169

Also, here is the "general" topic on your router. Read it.
https://forum.openwrt.org/viewtopic.php?pid=175777

That said, please don't expect all the answers to be handed to you. That really isn't what openwrt is about.

Also, I repeat: please read the wiki. It clearly says:
To be able to use the UART on MR3220V2, TP18 to TP38 and TP28 to TP48 should be connected.
(which is basically the same as mentioned in that other topic)

The wiki furthermore says:
Now connect a serial hack adapter (DKU-5, CA-42 or similar containing the PL-2303 chip) and away you go!

If you had read that yourself you wouldn't have needed to ask whether that cable would work.

Again, please read here:
http://wiki.openwrt.org/toh/tp-link/tl-mr3420#serial

-> Not trying to annoy you its just that the wiki/forums contain so much info, yet you seem to be asking the same stuff again. If you have any questions let me know, but also try to read some yourself. Hope this helps

(Last edited by Boompje123 on 5 Jul 2013, 14:47)

Look at my thread:
https://forum.openwrt.org/viewtopic.php?id=42169
I know, it's troubling, i connected TX, but i burnt RX.

Thanks again. I am looking at Wiki Link. ( though 1 image linked is broken )

Wiki Says "To get the serial connection work reliably, you have to connect a 10k pullup resistor between the TX and the 3.3V pin. This is because the TX pin is connected to a voltage divider (2x5.6k) and a capacitor is put between the real pin and the TX connector"

What is 10k Pullup resistor. Where i can find this? Is it available on Ebay.in or Ebay.com ?

This router got any other port like Jtag ? I haven't yet opened case. Collection more info to make sure i can dive in.

(Last edited by nokiaberrygenius on 5 Jul 2013, 16:37)

Guys i have one more question , i ordered that cable called c-42 nokia. But it will take some time for it to arrive.

MY PC got this port

Can i use this for Serial Connection to router?

(Last edited by nokiaberrygenius on 6 Jul 2013, 03:54)

I am confused some posts says "VCC is not needed" while other says its needed.

GND/TX/RX are on this serial port , can i directly take wires and solder them to PCB.

Can't this VCC for 3.3 V pin supplied externally?

VCC is not needed

GND - GND
RX - TX
TX - RX

just wait for your cable to arrive. Usb > serial is the way to go

Still no Serial Connection. Tried Swapping both RX and TX. Nothing yet.

I think WIKI Article is Flawed and someone needs to update instructions.

Update:

Following Wiki Article posted here http://wiki.openwrt.org/toh/tp-link/tl-mr3420

Tested all connection with Multimeter.

Still no serial connection. I get nothing on Screen.

(Last edited by nokiaberrygenius on 2 Aug 2013, 12:17)

Do loopback test your cable first before connecting to router's serial pin header.

- connect rx and tx of usb-ttl cable by shoten it directly.
- open putty terminal set the proper com port which your cable connected.
- type some character on keyboard if it echoed back to terminal your cable is ready for use if it not, check your cable driver.

If you use CA-42, this cable need external vcc, you can manage this from router vcc pin ( pin number 4 on most tp-link routers).

MR3220 serial pin line up , take a look at bold white strip next to it is TX pin next one is RX , GND and VCC.

I hope this will help you.

Did, exactly what you said.

Here are outcomes.

Whatever i type on keyboard comes to my screen.
I have USB to TTL Adapter with 3.3 v and 5v pins.

Still i connect those TX , RX , VCC with 10k ohm resistor in between VCC and TX , i get nothing on Screen.

Already made jump as stated here http://i.imgur.com/hYrsSKq.jpg