The first thing I tried was to change the password (iPhone 4 4.3.3) after jailbreaking but the MobileTerminal crashes upon launch. Same story after a phone restart.

Edit: Figured out the problem. Looks like the MobileTerminal in the CYdia repo doesn't work for iOS 4.0 onwards. The following is a working version from the author of the app:

http://code.google.com/p/mobileterminal/wiki/Installation