I’m coming in a bit late to the game here. I found this thread after I upgraded the firmware on my DIR-655. I have hardware version A1, and my Roku m-500s were working fine wirelessly with firmware 1.02. I upgraded to 1.21 and my Soundbridges could no longer see Firefly over the wireless. I tried for an hour or so adjusting settings to no avail. Finally I decided to downgrage to 1.02 again.
After some searching on D-Link’s site I saw that they do not have firmware version 1.02 available for download directly. Snooping about on their ftp server, I was delighted to find it still there. Unfortunately downgrading directly from 1.21 to 1.02 was not possible. I was finally able to get back to 1.02 by downgrading from 1.21 to 1.11 then to 1.02.
If you’re having trouble and your router is able to run version 1.02 you might want to give this a try. Be sure to back up your settings first!
You can find the firmares here:
ftp://ftp.dlink.com/Gateway/dir655/Firmware/