I had to give up on the range extender as well. Very disappointing. I am now using the Almond+ in AP mode but this required me putting the pouter in a place that had an ethernet cable, which was less than ideal. I do have the R65 firmware.
The problem I had with range extender is that it would establish the link to the main router without any problems but could never connect clients to it (they would never get an ip from the main router). I tried various combinations of settings and SSIDs and resets but it just would not work. To be fair, it might be an issue with the firmware on my main router (ASUS RT-AC566U running Tomato Shibby 1.21 firmware) but after two days I lost patience. I am an IT pro with a long history in networking so this does not bode well for an easy to use, out of the box setup that is being advertised for the Almond+.
With AP mode, it worked right away but it is not quite the setup I wanted.