With version 1.x and 2.x
download viisa 192.168.0.100 1
download - command to put the switch into download state
viisa - the name of your file in your tftp directory (usually was called viisa up to v 3. something)
192.168.0.100 - replace with the IP address of your tftp server. We use tfptd32.exe, works fine. Be sure to copy the download files to the working directory for your tftp server, it much easier than adding the path to the download & copy command lines.
1 - the vlan port you are connected to.
Once you get to version 3. something the syntax changes to copy tftp SW_image & EW_archive, etc.
download ? on the command line will give you the correct syntax for v 1 & 2. Copy tftp ? will give you the correct syntax on v3.
Between version upgrades make sure to reboot. Be sure it's done by looking at the version from the command line before rebooting. If you reboot before its done, you chance screwing the pooch.