I use the same router. On my router the firmware (1.9.2.7-7f) run fine.
Check first the version. version 1 is a broadcom wlan-modul. Else you have version 2. If you don't know, it doesn't matter. Only wlan don't work if you take the wrong one.
Then use the program call 'firmware restorator'. You find it on the cd of your router. It's a little bit difficult to get a connection, but it works! See also in your manual how it works.
After that do a reset of your router and everything is fine!
Good luck!