tftp file size limit

Question: I tried to upgrade the IOS on a Catalyst 6509-Sup720 with tftp but I get this error in my tftp server log: "File is too large for tftp protocol". Is this a bug in my tftp server software? If not, how can I upgrade the IOS? Oh I forgot to say that the file size is almost 80MB.

Answer:
Originally tftp protocol supports maximum file size of 32MB, however some changes have been made so tftp can support up to 4GB. But to be practical you need to upgrade your IOS using FTP or RCopy.
To do this with FTP all you need is replacing "tftp" with "ftp" in the commands you used before:

enable
copy ftp: sup-bootdisk:

Of course you need an FTP server instead of a tftp server as well.

If your ftp server requires username and password you have too define them in your switch:

conf t
ip ftp username xxxx
ip ftp password yyyy