There are a number of hidden debugging aids that you can access using the Graffiti shortcut mechanism.
These debugging mechanisms can drain your battery quickly or cause the loss of all your data. Use them judiciously.
The Graffiti shortcuts are accessed by writing the Graffiti shortcut character (a cursive lowercase L) followed by two taps (the two taps generate a dot, or period), followed by a specific character or number. It’s common to open the Find dialog before writing them. (Find has a text field that’s available in all applications, and it’s nice to have the feedback of seeing the characters as you write them.) Here is a complete list of these shortcuts:
Enters debugger mode. The device opens the serial port and listens for a low-level debugger to connect to it (for example, the unsupported Palm Debugger application). Do a soft reset to exit this mode.
Enters console mode. The device opens the serial port and listens for a high-level debugger like CodeWarrior to connect to it. Do a soft reset to exit this mode.
Turns off the power auto-off feature. The device does not power off after idle time (although the power key still works). ...