So I bricked my Linksys WRT160NL last week, today the USB to serial device arrived by mail. The special thing is that it supports 3.3V on the serial port as opposed to the more traditional 5V that is used on PCs. A search on e.g. eBay for “rs232 to ttl” will show a lot of cheap devices you can get.
I opened the router and attached the cables that were included with the USB device to make the serial connection work. On the OpenWRT wiki some other information is included about using the external accessible serial port, but I didn’t want to risk frying the WAN/LAN port by fiddling with wires. So what I ended up with is this (click for larger version):
After this I followed the TFTP flash procedure as described here which worked like a charm🙂
I used Ubuntu 11.04 for this procedure with minicom (apt-get install minicom) and start it with minicom -D /dev/ttyUSB0. For TFTP upload I used the basic TFTP client, tftp (apt-get install tftp).