I've been reading OpenWRT, but I can't figure out which file to download to flash via the TP-LINK firmware update function. There's about a hundred files in /attitude_adjustment/12.09/ar71xx/generic/ . I've looked at the squashfs bin versions. But can't make the link between the hardware info page for the 850RE and the list of files. I see some AP136 and AP96 files, but mine is AP123 and I see none of them.

If you can point me to a flash-able all inclusive bin file or give me a getting clue what to look for in that list, that would be great. I've done DD-WRT, but that seems a little more straight forward than openwrt.

on the other post I linked you to the thread here https://forum.openwrt.org/viewtopic.php?id=46859 you won't find that file only in that link cause FriedZombie prepared that file like I said read and read carefully and if you have questions do it in that thread and as the post reads Download Images for the wa850 and wa750 Recommended by FriedZombie. comes with webgui (Luci) and compiled by me.
And as you posted you have done DD-WRT why you did not find this
TP-Link WA850RE
http://www.dd-wrt.com/phpBB2/viewtopic.php?t=171385
DDWRT on WA830RE v2?
http://www.dd-wrt.com/phpBB2/viewtopic.php?t=171908
Do not forget that, to see the files you have to be logged in the Forum.
I really suggest you to stay on DD-WRT you are familiar with.

I did DD-WRT on an old WirelessG device I had. I found OpenWRT link in the TP-Link forums first so went there for the TP-Link. So I have my 850RE all flashed and the LUCI up and running. I reset my root password. Now I'm just trying to figure out the configuration of a Bridged Repeater. I see a lot of config files/commands level type stuff on the Open WRT forums. Trying to find the GUI version of it somewhere. Still looking...

Wireless Repeater Video
http://youtu.be/3rbsh2zxPnk
This is the only forum I have found LuCi how to's you have to use Google translate
http://foro.seguridadwireless.net/openwrt/(tutorial)-modo-clienterepetidor-openwrt/
Part 1 Client only Ethernet Internet
Part 2 client bridge (routed) repeater
Part 3 WDS Repeater
If you get desperate don't make this mistakes
Do not flash back to factory firmware, Before you have to cutoff the boot part of the tp-link firmware image. ask FriedZombie to patch it for you
Do not hold the reset button to reset to defaults use LuCi System/Back up and flash FW/reset to defaults/perform reset

Thanks much for the assist. I also found that video and I'm all set. Up and running. Good speed throughput and so far very stable. I did use a different SSID instead of duplicating the main AP SSID since I've read multiple posts now about duplicating even though TP Link instructions say you can.

Danymarc's replies are no longer showing up. Could you advise on how you fixed? Getting extremely frustrated!

Ducayne wrote

Danymarc's replies are no longer showing up. Could you advise on how you fixed? Getting extremely frustrated!

I'm @danymarc I don't understand what you need

Don't use WEP for wifi security. If you are, extenders can be very slow. Switch to WPA2. That fixed problem for me.