Minor Description
I just noticed that the TFTPClient class does not support a block wraparound - hence, when the block number exceeds the max allowed by the rfc (65535) - about a 32 mb file - bad things will happen.
I can't find any rfc that specifies how the wraparound is supposed to occur, but this wiki page mentions it:
http://en.wikipedia.org/wiki/Trivial_File_Transfer_Protocol
And I am working on implementing a TFTPServer - and in my tests with the tftp client that is shipped with fedora, I have determined that that tftp client expects the next block number after 65535 to be 0.
So it appears that the TFTPClient should wrap its block number so that it properly supports larger files.