When I started the subdle activity of reflashing foneras with third party firmwares there was a lack of information on the whole Internet about methods of doing this without the always valid RS-232 method.
Now there is an opposite problem: lots of website speaking about step1.html, kolofonium, CAMICIA build, hex.out and so on but infos are generally confusing cause referring to outdated or too complicated methods (and I’m sincerely too lazy to get them a try).
I recently got a Fonera 2200, the basic model currently sold on shop.fon.com and – incredibile dictu – in this model Redboot is enabled by default! OMG P0n1es!!!1
The flashing method described above works also with previous Fonera 2100 A/B/C models, but you have to manually enable redboot before proceding. Ask Google for this.
So to achieve a flash with DD-WRT (sucessfully tested also with OpenWRT Legend mod) starting from whatever version of the FON firmware present on the stock hardware, follow these step: