I did this once and can't remember the command line to use to unpack a tar file from tftp to switch. I've tried the following and get error opening tftp even though it's running and permissions in place
archive tar tftp://10.0.5.53/html.tar flash:
The command should be:
archive tar /xtract tftp://10.0.5.53/html.tar flash:
If you get error opening the TFTP please check if it is pingable and also if there is not any firewall blocking the UDP port 69 and high ephemeral ports (49152 and above). Having a look into the TFTP server's logs might also be useful.