please someone help me, i got same device, i already soldering the serial and iam using Prolific PL2303 Adapter. when iam using "putty" there no respon on putty. how to fix it?
thanks, sorry for my bad english
Either you have the same problem as me, or your TX and RX are flipped, if the problem persists, then go over these:
- Is your USB to TTL dongle showing in 'ls /dev/ttyUSB*' and is it working properly? (connect ONLY THE DONGLE and short its GND and RX / GND and TX, it should show something in your emulator as a response)
- Make sure your emulator is set to 115200 BAUD rate and with no flow control
- Make doubly sure that GND, TX and RX are in the correct order
- Don't use VCC, use OEM power source
- If you soldered pins make sure they don't short each other by a bad connection (use a multi-meter) with its continuity test function and check the pins don't short each other via a bad solder connection
- If you tried the above... then welcome to where I am...
Tried following @tp-linkuser's directions, I'm pretty sure mine's is fully bricked to hell.
The process:
- Used pins to connect to GND, TX, RX, first try without soldering, no response, USB dongle disconnected sometimes from a bad connection, tried re-powering the device while connected
- Soldered the pins, USB dongle is stable and doesn't disappear from /dev/ttyUSB0, no output, re-powering the device while connected did nothing
- Bridged/Shorted GND+TX, GND+RX, no change, re-powering the device while connected did nothing, also experienced a few jolts trying to flip RX and TX (thought I did it wrong)
- Tried 9600, 38400 and 115200 BAUD rates to no avail (all without flow control) using "screen -fn /dev/ttyUSB0 BAUDRATE" (-fn for NO flow control)
- Tried to press the RESET button whilst connected, no change.
Result:
LEDs flash, 1 LED then the "circle" of LEDs, the same flashing cycle as before but no output given via serial port, device is probably completely bricked.
Possible causes:
- A few months ago, using a telephone cable to fix the serial port to the USB dongle I had experienced a power-outage while testing (weather-related, lightning strike), this might've caused damage.
- Soldering? (check pics, I didn't damage the board from what I can see, only the solder)
Pics (Can't do without them):
thank you for the information, but i given up, my usb ttl burning because i connect it to 3.3vcc on device to usb ttl and i dont have good tools to bridge that small point on the device.
By bridging he meant to short them if I'm not wrong, in order to change the serial mode (https://openwrt.org/docs/techref/hardware/port.serial#serial_modes), it's possible with a simple telephone wire.. you simply use it to "bridge" between two pins.. careful though... a bit unstable with your hands you will get jolted (like I did), I tried to do so with GND+TX and GND+RX.. no change... device is probably completely bricked... at least I can finally give it up.
As @freezeheat, any thin wire would do. You can also use your phone as a magnifying glass while working.
Check this for info about what to connect
And while you are at it, would you be so kind as to take a clear photo of those points as requested by @tmomas
Check the last reply in this post. It has some links to clever ideas of how to manage to get access to tiny little points. It's a different device, but can inspire you. Howto get easy safe serial access to the BT HOME HUB 5a (bthh5a) - #13 by mjs
The same thing happened to me, those who have trouble soldering the points on the board connect them directly to the point without soldering it (by hand).
As I said, I only use RX device(wa850re), and TX TTL USB adapter. 
RX -- TX
GND -- GND
In the image I see that the points are not soldering. @freezeheat @eza1
And to verify that the ttl usb adapter works, connect RX and TX to each other, type anything and you must see it on the screen
thank you for the information and tips you given to me, here some picture what i done before
i dont know what wrong i do everything that i found in internet and this forum but nothing appears in putty screen and the light only power on and it not blinking, but when i connect the device to lan it connected but with no ip, i scan using advanced ip scanner my device not showing in the list on scaning, is any way to unbrick this device without using serial?
thank you before
sorry for my bad english
Yes there is... you shoul've tried it before!
links from https://openwrt.org/docs/guide-user/troubleshooting/vendor_specific_rescue :
TP-Link forums: https://community.tp-link.com/en/home/forum/topic/81462?page=1
Youtube tutorials (should be the same as wa850re v2):
I added new pictures, I just want to know exactly what to solder before attempting it... which will be better for the Wiki as well.
You could ask other users who have the device. Though, from an image I found earlier (see in this topic near the beginning), it appears that the Tx point is likely to be the one closer to the serial header.
Please see the green lines.
These are the two pair of points you must short circuit.
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It doesn't really matter since you have to close both of them to have two-way access. I think that transmit will be the small one toward the bottom of most of the pictures.
I use small stranded wire for this. Strip off the insulation for about 2 cm, straighten and separate the strands then pull all of them back except one. Keep the main part of the wire attached intact to use as a handle. Pre-tin the end of that strand and then hold it on the board crossing the two points then melt it in place on both points at once. Use a knife blade to cut off the excess-- put the knife down with moderate force on the strand then pull the wire upward rather than press the knife hard into the board which could damage the traces.
Also of course this will be easier before soldering the square pins on.
Really great tips here.
In my case I just used a drop of tin on the tip of the soldering iron. The two points are so close that this unique drop was enough (one for each pair of points, of course).
Not really. I've tried all the known TP-LINK methods, no success at all.
Serial method seems to be the only one possible for this device. Hope I'm wrong thought.
Yeah you're right only serial, maybe i need buy another usb to ttl, thanks
Tried the same method, but I definitely burnt the trace track and with about 250 Celsius (482 F) using a canonical tip,
not to mention plastic melted from the serial pins (because of the tight space I touched it with the tip) and even applying alcohol to try and clean it failed... I pretty much ruined it by damaging the traces and letting plastic melt into them.
my advice, first solder the TX/RX breaks and ONLY using wire to bridge the connection then solder the pins to the serial port, use a heat sink if possible since the board has low heat tolerance(use alligator clip without insulation or a more professional tool for that)... a wire bridge is the safest and most legitimate way to do so, since you simply solder each end of the wire instead of a challenging wiggle of the solder tip that may or may not spread solder around and cause problematic bridges...
Well that's it for me... at least some good reference and photos came out of this.
Thank you @leomanias, @Hegabo and @tp-linkuser, I may have failed but it was a learning experience, check the Wiki, I tried updating some things and added some helpful photos.
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Just wondering... If sysupgrade firmware_stripped_or_not.bin is getting us Invalid image type., isn't there a way to modify the original stock firmware image so that the the openwrt will accept it?