I would like to develop a bash wrapper or something for this upgrade technique. I am sure you can do it.
I tried doing
echo python -c 'import pty; pty.spawn("/bin/bash")' | nc -l -p 8080
This gives me a weird string format errors. So I popped the python command in a text file, and did
cat command.txt | nc -l -p 8080
It gave me a prompt, but no interaction. I'll figure out a way soon enough. Upgrading ordinary netcat shells is really dope. I hate the ordinary netcat shell.