Bricked - solid amber (orange) power LED (wrong fw)

Hello community!

I have successfully flashed Tomato FW on my Netgear WNR3500Lv2. I decided to return to OFW, however I accidentally flashed WNR3500 instead of WNR3500L (downloaded from Netgear official WWW)...

I've read this article and couple of threads:

http://www.myopenrouter.com/article/36609/How-to-Debrick-Your-WNR3500Lv2-Using-Windows-and-a-USB-TTL-Cable/

http://www.linksysinfo.org/index.php?threads/wnr3500l-v2-dead.36762/#post-178251

I've tried 30/30/30 resetting. I get 3 ping responses from router right after powering on. I've tried tftp but get timeout error all the time (I guess response window is too short).

So I guess I need USB-TTL cable and try to run TFTP mode on my router like in the article above? Shipment from Amazon en eBay would be pain in the ass to Poland, so I have to order from Allegro. This cable would be OK (it has to be 3,3V right)?

http://allegro.pl/pl2303-usb-ttl-rs232-konwerter-przejsciowka-fvat-i4365275197.html

Regards and hoping for your help!