Just google for bash 770 package:

http://www.math.ucla.edu/~jimc/nokia.../binary-armel/

I think this is one I installed, although I got it from another site.

Note that you shouldn't change /etc/passwd to make bash your default login. I'm not sure what happens but this locked my machine into an eternal reboot and I had to reflash the operating system. Instead, just call bash whenever you start xterm.