I took my R7000 from stock firmware to the 07/24/14 (24710M) build of Kong's DD-WRT. It seems like this release has a bug in it, because it's seemingly not possible to upgrade or install different firmware.
I've tried the 08/01/14 release of Kong, old and new releases of the Netgear stock firmware, and the bootstrap version of DD-WRT. All of them result in "upgrade failed". I've tried erasing nvram, holding down the reboot button the back of the router after reinstalls, and every other trick that's been mentioned on this forum.
Is my R7000 going to be stuck on this release of Kong DD-WRT forever? How do I get any other firmware on it?
Yes this is a bug in 24500/24710 which can sometimes cause this behavior, just og on to the router via ssh/telnet and run commandline util to update:
ddup --flash-latest
latest build, also fixes the webif upgrade bug.
It has also been reported by someone on the dd-wrt forums that downgrading to an older kong release works. Then you can upgrade from there.
Kongs command line method is the suggested method.
It works great!