Hi Willem,
For the WRT54G we recommend DD-WRT build 22118, from here:
http://download1.dd-wrt.com/dd-wrtv2/downloads/betas/2013/07-24-2013-r22118/broadcom/dd-wrt.v24_std_generic.bin
You may need to upgrade to 21061 first:
http://download1.dd-wrt.com/dd-wrtv2/downloads/betas/2013/03-25-2013-r21061/broadcom/dd-wrt.v24_std_generic.bin
Please reset the router to factory defaults from Administration>Factory defaults after replacing the firmware every time.
You’ll no longer be able to run remote commands with the new build, but it will work flawlessly. Old builds are very old now and can’t communicate perfectly with today’s devices every now and then.
Steve