Hi,

I've made it: I bricked my TP-Link WDR-4300. (By re-writing the "original" Firmware, i think there was some kind of error ...) So far, so good.

I connected it to my PC via the Serial connector (see http://wiki.openwrt.org/_detail/toh/tp- … tl-wdr4300 ) using 115200 bps at 8N1 and can see some strange console output:

]µ
]ý9!#¿
¿åës'=/¿¿¿e{åëUFK¤¦»ªêª:ºú«jÚ
              µ]µõ¿-#¿s'=/£¿U-#1¿3-57¿=77åëêÊúúû۪ʪºú+êÊJZËúËËûûû+ëT_Võû++++Ëu¿_oM¿«åë±Ëêûû{ûËÚûû{ëë»+ëMÑé¶öÛêZÛªZZ˪Zû{[»ë+ëOÑiÔµT µ]-¿9!%'55åëÓÑéö«ú*ë5/åëèU]
í         Õ                                         µ
  Åý-#¿-#1¿i5'¿m%=15¿£££¿W!!¿;-1¿#9!%57¿=%gKe}¿u[[a[¿¿!¿9!5½Þ¯UÛ

this repeats forever - I think this is the bootloader.
Can anyone help me - Why don't i get some "good" / readable output?

have a nice day,

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                                         5ƯỞŨỄỞỎỲỞậƯỸ59!9!#ƯẦƯỘỞăẻs'=Ỹ/ỀƯƯỞƯe{ăẻ                                    UÔẾúỪếỌêế:ỨúềỌjÚ
                *ếỨ*ẻăẻ[ấổũũũẺếÚjê:*ẻaỀƯƯƯỸ5'ăẻuƯƯƯỸ5'ăẻểÓứìũũẻẾẾỹỪũ

Same Problem exactly with TL-WA-701ND

please help us guys!

(Last edited by vetusa2 on 16 Jun 2013, 23:12)

on some routers, with my usb ttl adapter i have to pull tx high with a 15K resistor. see if this helps you. Even on routers that do not explicitly state this on the wiki. i have had to do this.

connected one exactly like this at the end of the tx (tplink side)

http://kc.koncon.nl/ipsonlab/images/resistor_flip.png

black screen!!

just to be sure (since none of you guys mentioned it, and even the 4300 wiki page doesn't really get deeper into it), are you using special 3.3V usb-serial adapters? and did you just connect Tx, Rx and GND? It is best for us to understand, if you point out every step you have taken.

(Last edited by MBS on 17 Jun 2013, 08:40)

I directly connected the Tx (yellow in the image)  to the Tx on my 9-pin serial cable (Pin 3), th Tx (blue) to the Tx (Pin 2) and GND (red) to GND (Pin 5).
On my PC I'm using PuTTY on COM1 (this is correct, as I get stuff transmitted) / 8N1 (no flow control).

Also, putting an 10k resistor (had no 15k) between Tx did not do nothing but blackening my Console (which is no wonder with 115200 baud). Without the risistor I still have the rubbish output.

A friend of mine just told me what the problem is: a standard RS232 output is -12 to 12V, whereas the one in the router seems to be 0-3.3V. A resistor will not do the trick as the built-in inductivity will cancel the signal.

[EDIT]THIS MEANS THAT THE DEVICE COULD BE BROKEN WITHOUT THE USE OF A PROPER CONVERTER![/EDIT]

So there are only several solutions left:
a) getting an Adaptor that makes 3.3V Serial readable via USB (see Amazon etc)
b) getting a converter (converting from Router 3.3V to PC 12V)
c) using another endpoint which has a 3.3V serial port - e.g. an Raspberry Pi.

I will look for some things and let you guys know what works.

Thanks so far,

(Last edited by huber_stefan on 17 Jun 2013, 16:15)

Almost every router out there will require 3.3v and most of them are not friendly to higer voltages, i hope you did not damage anything.

here is some photos to describe the situation and my problem

(Last edited by vetusa2 on 17 Jun 2013, 17:40)

And another one who didn't read carefully!

YOU NEED USB-UART ADAPTER WITH VOLTAGE LEVELS 3,3 V!
NOT USB-RS232 ADAPTER!

You can brick your router with that kind of adapter (USB-RS232)!

if you look closely in my board you will see that i didn't connect any wires to the 3.3v pin ,but instead i welded 3 wires which are TX/RX/GR and when i start to putty into the board i hit the power switch of my tplink.....so it can't be bricked!

TX=blue wire
RX=green wire
GR=red wire

(Last edited by vetusa2 on 17 Jun 2013, 18:32)

now i have a question

can this cable do the trick as the USB-UART cable?

http://sleclire.blogspot.com/2010/09/cl … cable.html

the problem is not only the VCC pin, also TX and RX could be damaged by too high voltage from you pc/adapter.

be sure to use only 3.3v ttl serial adapter!

the nokia ca-42/dku-5/any clone should be ok!

OK, again:

YOU NEED USB-UART ADAPTER WITH VOLTAGE LEVELS 3,3 V!
NOT USB-RS232 ADAPTER!

i will try the USB-UART ADAPTER

any specific model number to be compatible with WA-701ND ?

can you guide me on how to connect it to my tplink?

(Last edited by vetusa2 on 17 Jun 2013, 19:39)

For example CP2102: http://www.ebay.pl/sch/i.html?LH_PrefLo … &_sc=1

And remember: connect only this 3 signals: RX, TX and GND.
Power the router from power adapter. The USB-UART adapter has its own power direct from USB.

TX on adapter goes to RX on router.
RX on adapter goes to TX on router.
GND on adapter goes to GND on router.

(Last edited by pepe2k on 17 Jun 2013, 19:41)

thx pepe i will try to buy that and let you know what happen

Hi together,
news:
connected a Rasperry Pi to my WDR-4300 (Tx <-> Dx, of course) and got some output:

U-Boot 1.1.4 ”¢Y,SH‚Š’jŠ‚ÒŠ‚Òª¢Êj)5)ª-boot DB1²˜C¡H¨Hˆ$iéA 128 MB
id read 0x100000æ³C!+5¡æize 8MB, sector ¬«¹Ñy 128
Flash:  8 MB…Using default enviòË««çÑ5
PCIe Reset OK!!!!!!ŠRKš•É¥…±5Out:   seréXH¨%Éé@  serial
Net:   açN&}•¹•Ñ}¥¹¥Ñ¥…±¥é•¹\.
No valid addråóó é®£¶X.•    U5¥¹Íixed addre³®Hø wasp  reset má®-§,ÓÓj(ÿWASP  ----> S17 ÐÈÙ ªCá: cfg1 0x7 cf§™˜^S)¢j(ÿeth0º âẢY'VJ•éa8:41
athrs17_òåçßi®Z/'ÒÖ«±•Ñ•5eth0 up
eth0
Autobooting in 1 secï·²®Hø## Booting image at NI‚‚‚‚òòòj)@Uncompreó®–ëZ•É¹•±’mage ... Too ±Z©¹½µÁÉ•ÍÍ•‘ætreamLZMA ER’JŠjjÕÍс¤ESET board tY¬Ë•Éÿ

U-Boot 1.±—šJQY,SI‚Š’jŠ‚ÒŠ‚éÕÑR

U-boot Ä¡L&SH¨H¨Hˆ%ké@ 128 MB
id read 0x100°˜˜³VHÈÅ…Í¡æize 8MB, secôKÇount = 1²œC!+5¡é@ 8 MB
Using default e®»Z®Ë««åÑ5
PCIe Reset OË¡¡¡¡¡HC¡”Kš•É¥…±5Out:   serial
Err:  ®–++Å5Net:   ag934x_enetßZ+‹¥…±¥é•¹\.
No valid aä²¹Y®.TËiÅ…Í¡¹@Using fixåä á䤹Y®®Hø wasp  reseô[X®-§,ÓÓ    j)ÿWASP  ----> ÓL    …ʁU
: cfg± °ø· ,Ö–    ÂÝe14
eth0: ba:be:faºã庰¸šLCáathrs±·ßò姕¹¥ÑéAcomplete
eth0 up
eth0
Autobooting in 1 óY¬Ë‹55db12x> 
db12x> tftpboot
dup 1 speed 10°˜Cá*** Warningº·%½½ÑÌile name; using ’“)
á…0.im种ŠÕ³Zë*Ñ¡ÁAdevice
TFTP fro®–˕Ɂe92.168.1.100; ouòR*¤,–«ḱÕs 192.168.1.±LLC!T‹«å…µ•N6F01A8C0.imç’©Hˆê+EÃddress: 0x81000°°°
Œ+E¥¹éA*T T T T T T T T T T 
Retry count excåY֚хÉÑ¥¹Âgain
*** Warning: no bïïô æ©¶Y$+Õ•íAusing '6F01A8C0.©[ÖRH¨5¥¹Êth0 device
Tƪ¨–ë«4•ÉٕɁb92.168.1.±˜˜'ҫɁ’P address is 192®LrŠrŠŠŠj)¥±•¹…µ•'6F01Á¸Ã°®©[Ö’©Hˆê+EÁddress: 0x810°˜˜˜LC!ê+C¥¹é@*T T T T T T 
Abort
db12x>

As you can see data receiving seems to work fine as I typed tlp[RETURN] at some time and came to db12x>. Also, tftpboot command was executed, but as I see mostly rubbish this doesn't help much...

What is wrong now?

Thanks for your help up to now,

Check your cables and connections.
Did you connect GND between RPi and WDR4300?

connections have been checked with multimeter, everyone at 0 Ohm resistance and no connection between them, but I got ~10kOhm between GND and TX (on the router side, even with no cables attached)
Yes, I connected GND <-> GND, Tx <-> Dx and Dx <->Tx.

Are you sure the tx and rx cables aren't touching eachother while connected?

That 10k Ohm is probably internal/external pull-down and it's OK.
What connection settings are you using on RPi side?

Yex, Tx and Dx are not touching / connected (measured it with a multimeter).
Settings are 115200 baud, 8N1 without flow control.

I think I can live with the rubbish stuff.

My next problem is that somehow (after tftpboot 0x81000000 openwrt.bin) the router won't connect to my tftp server. (plugged in at the blue "Interet" port, all firewalls disabled).
Once it connected but aborted the file transfer... strange stuff.

thanks so far,

Ah, i just plugged it into another eth port and it worked like a charm!

Thank you for all your help!

summary:

1. connected Router (Serial 3.3V!) to Raspberry Pi (Serial 3.3V!)

2. didn't mint rubbish output

3. did it like the WDR4300 Page states

again, thank you very much, all!

maybe the usual 10k from router tx to router vcc could help? just curious..

There seems to be such an resistor already, when I measured the resistance between Tx and GND, it was 10 OHM whereas all other resistances were INF (turned-off).