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?
This is something that really deserves more efforts. I've invested a few hours back and forth on it, but always with same result: a non-bootable device. 
what have you tried?
I think. I have not tried.
It has to be stripped of the header of the original firmware with hex editor up to the sequence in hex 01 00 00 00 54 50 2D 4C 49 4E 4B (cut the first 0xE684 bytes) and flash with the mtd method.
*Original Firmware
https://static.tp-link.com/2018/201802/20180209/TL-WA850RE(US)_V2_171228.zip
*Firmware stripped
sha1: 1044b37ab4fe5f0895794ab436ee4f54d196f167
NOTE: I think. I have not tried.
Hi,
I've tried these 3 options, following this order:
- Using the firmware file already stripped, available here: https://drive.google.com/open?id=182lVNe3GPChYFoTjHx6QT2_-z8et8gaW
- The standard one for TP-LINK devices: "Cut the first 0x20200 (that is 131,584 = 257*512) Bytes from original firmware";
- The one you described;
Always same result, non-bootable device.
IMPORTANT: I'm trying to remember but I can't get it now, if I used mtd method or not. This may address the question. But I guess I did, once the device was doing the looping boot anyway.
Using mtd or flashing via serial, same result. Non-bootable device.
Really don't know what else to try to back to stock firmware...
I think. I have not tried.
It has to be stripped of the header of the original firmware with hex editor up to the sequence in hex 01 00 00 00 54 50 2D 4C 49 4E 4B (cut the first 0xE684 bytes) and flash with the mtd method.
*Original Firmware
https://static.tp-link.com/2018/201802/20180209/TL-WA850RE(US)_V2_171228.zip
*Firmware stripped
https://www94.zippyshare.com/v/C7RB6EoI/file.html
md5: adfedabce6ea3ff732e3cd99bbe0835b
sha1: 1044b37ab4fe5f0895794ab436ee4f54d196f167
*mtd method
mtd -r write /tmp/firm.bin firmware
*serial method
tftpboot 0x80060000 firm.bin
erase 0x9f020000 +0x3812E6
cp.b 0x80060000 0x9f020000 0x3812E6
bootm 0x9f020000
NOTE: I think. I have not tried.
@SantiagoAcevedo @leomanias
Right, this is the one I tried. Original and stripped. No luck so far. Thanks.
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