4a6afbed__are_available_for_developers___Notes
[Character] 1 [Description] The device enters debugger mode, and waits for a low-level debugger to connect. A flashing square appears in the top left corner of the device. [Notes] 
This mode opens a serial port, which drains power over time. You must perform a soft reset to exit this mode.
What "hidden" shortcuts are available for developers?
Notes