I have 2 WiFi routers TL-WR840n V4, I found upgrade on TP-Link website and upgraded both of them, then I found some latest un-official upgrades (Open-WRT) and tried to upgrade one of my routers (connected via WiFi) and it did not work (bricked I think so as all lights blink). unfortunately I used tftp recovery method using open-wrt recovery bin and my router became fine, but I dislike the page (web interface) now I am desperately looking for a solution to bring back my router to its original firmware (official), 

I tried {dd if=original_firmware.bin of=tp_recovery.bin bs=512 skip=1} and it worked but my WiFi MAC Address is now FF:FF:FF:FF:FF:FF and when I tried to connect my phone (Samsung J3 Prime) to that Wifi my phones wifi started turning off and on rapidly (and this ended when I turned my Router off). I have two Questions.

1. Can I have official recovery file (for tftp recovery)

2. Can I extract recoverybin file from my other router(which is perfect)

3. Can I just change WLAN MAC Address of TL-WR840N V4

Please help