Decided to try tomato on the Netgear R6250 since it has a nice UI. Upgraded from kong-dd-wrt to the latest stable download for Advanced Tomato.
There is an instruction on the tomato page that says, BEFORE UPGRADE you need to telnet to the router and issue a command to get the http password, I decided not to do that since I was going to reset after upgrade. (http://www.polarcloud.com/tomatofaq#why_doesnt_my_password_work)
The factory/hard reset for Netgear R6250 as per the user manual is a simple 7 second press of the reset button on the back, of course i didnt remember this and did not bother to look up. I just pressed the reset button for more than 20seconds but the router did not reset, then I tried the 30-30-30 reset which did NOT work either. Instead a simple press of the reset button for about 7-10 seconds is all it needs!
(A little knowledge is a dangerous thing or in my case was a lot of wasted time 🙂 )
(Btw, the tomato firmware has 2.4Ghz issues)