Well... if you brick your router you have at least one last chance to recover it
Oh... by the way... be sure you have tftp client and a working firmware ;)

  1. Start your Asus WL-600g keeping the reset button pushed

  2. Force your network device to one IP in 192.168.1.2-192.168.1.254 range (note: you have to be wired-connected to the router)

  3. Start your ftp client (you will have a "tftp>" prompt)

    • tftp>[just press enter a couple of times...]
    • tftp> verbose
      Verbose mode on.
    • tftp> trace
      Packet tracing on.
    • tftp> rexmt 1
    • tftp> binary
      mode set to octet
    • tftp> connect 192.168.1.1
    • tftp> put WL600g_1.0.3.3.A.trx

      .....[ now you will receive a lot of the following messages].....

      sent DATA
      received ACK
      sent DATA
      received ACK
      sent DATA
      received ACK
      sent DATA
      received ACK
      sent DATA
      received ACK
      sent DATA
      received ACK
      sent DATA
      received ACK


      .....[ then some more messages].....

      sent DATA
      received ACK
      sent DATA
      received ACK


      .....[ then it should finish :) ]

  4. Reboot your router keeping your finger crossed


Note: your router configuration MAY be restored to the original one (not always)