From ModMyiFone - Wiki
If you want to learn how to Problem Solve your phone here are some suggestions:
You must have:
BSD Subsystem, terminal and openssh installed on your phone.
terminal or command line on your computer
ssh to your phone
To do this:
Open terminal/command line on your computer
Then type:
ssh root@yourip <enter>
Enter your password: dottie or whatever you changed it to. <enter>
(If your password is dottie change it!) the command is: passwd <enter>
Some helpful terminal commands are:
cd - this lets your change directors
ls -lists what is inside the directory you are in
ls -al -lists hidden files that ls won’t show you
pwd -this is the working directory you are in
./appname -will run a app that you are in the directory of
reboot -will reboot your phone
ctrl +c -will end currently running commands
pressing tab on your keyboard will auto complete
While using the installer.app
If something gives you an error try this:
1. Ssh to your phone
2. Cd to Applications (cd /Applications/Installer.app)
3. Run the installer app ./Installer
4. Now on your phone try installing the app again.
5. IN terminal you will be able to see the error and more details about it
6. Go to this url and paste the terminal text: http://pastie.textmate.org/
7. Paste the new url it gives you into irc with your problem.
8. Run the control-c command in the terminal window and then reboot your phone if needed
