it's because you flashed the factory-to-ddwrt file from openwrt - so it bricked. factory-to-ddwrt is for flashing ddwrt from factory firmware, as the name says
GreyDoc to the rescue
He sent me this via PM, something i couldnt find anywhere else, step by step unbrick
You bricked your router, but we'll figure it out.
The problem was that you flashed DD-WRT directly from OpenWrt. That's a big mistake.
DD-WRT should be flashed from stock (factory) firmware only, otherwise it bricks. You can't flash from openwrt to ddwrt or from ddwrt to openwrt.
So, you should have flashed back to stock firmware from openwrt (and that's not as easy as just flashing a factory firmware directly from openwrt, since it will also brick) and only then from factory firmware flash the factory-to-ddwrt file that I provided.
So you'll have to unbrick your router with TFTP. I will try to guide you to get DD-WRT on it, but first you have to flash a factory firmware with TFTP. Here's a good guide:
1. Download firmware from TP-Link http://www.tp-link.com/resources/software/TL-WA7210N_V2_140730.zip
1b. Make a new folder and extract .bin file from the .zip file
2. Rename the Bin file to wa7210nv2_tp_recovery.bin
3. Disable all network adapters you don't have plugged into the router
3b. Set the IP address on your PC to 192.168.0.66 (if it doesn't work, try 192.168.1.66), default subnet mask, and NO OTHER SETTINGS.
4. Install TFTP software http://tftpd32.jounin.net/tftpd32_download.html
4b. Run TFTP Software
4c. Within TFTP, browse to new directory.
4d. Ensure within 'interfaces' you see the above 192.168.0.66 IP
5. Hold WPS/Reset button while router is cycling, the 'lock' light should stay illuminated.
6. Router should grab the Bin file and restore automatically.
7. Thank the good TP-Link Devs for including this feature.
2) Transmission Power (Tx-Power): max 26dbm country code is BZ ( How up to 27 dbm(Official tp-link firmware up to 27dbm))
Hello, how do you reach 26dbm?
I upgraded to the same version as you (openwrt-15.05-rc3-ar71xx-generic-tl-wa7210n-v2-squashfs-factory.bin 15-Jul-2015 18:46), flash without any external antenna attached, but after setting in advanced settings country code to BZ the maximum power I can set is 12 dbm....
When it is connected/associated sometimes I can set 16 dbm max (too low!).
I tried almost anything, also openwrt 15.05.1, ddwrt, Jow's reghack and reghack2, but it is impossible for me to go up to 12 or 16 dbm.....
Moreover I cannot flash the m3020 14.07 openwrt and apply the jow's reghack (jow's reghack was for 14.07 I think), nor through the web interface (tp-link or openwrt), nor via tftp. tp-link and openwrt say that cannot flash the file, forcing via tftp I cannot reach the lan.
My problem is that I have the WA7210N v.2 with external grid antenna and an amplifier.
In test mode, the stock firmware, latest version, cannot connect with this setup at 27 dbm; at <20 dbm it connects but it is very unstable.
I was not able to have signal with the ddwrt.
At 12/16dbm the openwrt is very stable but it has a very low output power, so my goal would be to test and install the openwrt at least with an output power of 20 dbm to see its stability.
Thank you to anyone who will point me in the right direction!
I also upgraded my TL-WA7210N v2 to openwrt-15.05.1-ar71xx-generic-tl-wa7210n-v2-squashfs-factory.bin and it works very well although the internal antenna is not working and also the transmission power is too low.
I would like to go back to stock firmware but now I don't know how. I've looked all over the internet (spend hours turning back at the same websites over and over again trying to find a solution) and I cannot seem to find a stripped firmware from OpenWrt to stock.
flash the attached stripped WA7210Nv2 factory firmware directly from OpenWrt web interface to go back to stock.
edit - do not flash this from DD-WRT web interface! the file must be used only for reverting back from OpenWrt web interface.