I am trying to use "boot system tftp ://10.16.130.182/c2800nm-advipservicesk9-mz.124-15.T8.bin" in order to upgrade the IOS of my 2821 Voice Gateway but after executing the above command, all the GW does is just changing the line but nothing happens. The configuration register is set to Configuration register is 0x2102. Do I need to change it tyo 0x2101? Why the GW doesn't boot through tftp. I can download from the router to the tftp server but not in the revers direction.