I tried lotsa times to update the firmware (now is 1.9.8.2), everytime the router hangs during upload and only a manual reboot will make it work again. Any ideas ?
try first resetting the router to factory defaults, then try an upload.
be sure after updating the firmware you need to reset to factory defaults again, to make sure no settings are left behind:)
if that still doesnt work, try TFTP
search the forums for it, it works good;)
if that also doesnt work... try the asus firmware update tool:p