This happened a couple months ago, so I don't remember which was the version I was using, but I was trying to update my Fonera to a newer version of DD-WRT and it got bricked in the process. I just got into solving this problem some days ago and since I couldn't access it through telnet, I managed to get a USB-to-serial kind-of adapter and this is my setup:
This way I can access it through serial and this is what I get:
After this, everything starts again from the beginning and the output is almost the same, being the only differences in the gibberish part, so won't consider it relevant.
The problem here is that I can't seem to send the Control + C command to abort the boot script! I've tried an handful of apps in different OSes (Mac OSX - CoolTerm, Serial, Putty / Windows - Putty, HyperTerminal, two others that I can't remember the names) and I wasn't able to have any kind of success.
The adapter has 2 others leds besides the red (indicating power), one green for TX and one blue for RX. When the router is printing something in the console the green one (TX) lights up and when I press Control + C the blue one (RX) lights up too, so I just can't understand what is happening.
Nothing different, still the same. Tried with another cable (the brown one that you can see near the adapter) and checked if it's rightly pushed into the adapter and still can't Control+C the boot script.
Sorry for the late response, but I've managed to unbrick my Fonera, although it wasn't through serial connection but by using telnet!
That Gargoyle stuff didn't work either so I searched a bit more and found the following snippet for telnet connection in OpenWRT documentation, which worked for me - all my previous attempts to connect through telnet didn't worked at all before this:
Well, that's a good question but I don't have an answer for that. The USB-to-serial adapter wasn't mine and since I could access Redboot through telnet to solve my problem, I already gave it back to the owner as he was in need of it for some Arduino related stuff.
But I'll ask him if he lends me it again this week so I can try that in a couple of minutes and leave feedback here.
I have the same problem. Did you ever manage to make the connection work?
I found this old Fonera (stock fw 0.7.1 r5) lying around and decided to put DD-WRT in it. For some reason, Ctrl-C cannot be used to cancel the boot process and I'm unable to enter RedBoot to update firmware. Also, as it has never been flashed, I'm unable to use telnet to connect (Gargoyle/FonFlash needs that also). Apparently theres no other way to enable telnet than to use serial connection (there was a dns hack but the servers are now gone).
Like OP, I've tried different os's, systems and programs for the serial connection, and tbh used too much time changing the settings such as flow control. I'm using a bit unorthodox serial connection by using Arduino as my USB to serial converter, but I don't think that it matters as there has been problems with different configurations also.
I was trying to search some information regarding the problem, and could find actually quite many threads regarding this but no solution. Problem, that is, that Ctrl-C does nothing when using serial connection. So, does anyone have any more ideas what to try? Thanks!
(Sorry for resurrecting an old thread, couldn't find a rule against it, I hope it is ok.)