Your development system's boot behavior is largely affected by the positions of the DIP switches on your board (typically at S1). There are essentially five (5) boot modes:
Normal Boot. When powered up or reset the device copies the OS from onboard flash to RAM and then boots. Development systems ship with S1 set for this mode.
Open Box Upgrade. When powered up or reset the device copies all ADS boot files from an installed ATA storage card to onboard flash and then presents the debug menu (see below).
Sealed Box Upgrade. When powered up or reset the device copies all ADS boot files from an installed ATA storage card to onboard flash then proceeds with a normal boot (see above).
Boot from ATA. When powered up or reset the device copies the OS from an installed ATA storage card directly to RAM and boots (onboard flash is unaffected).
Debug Menu. When powered up or reset the device echoes a debug menu to the Debug Port (see section 5.2).
The following table outlines what effect different switch settings have on the boot mode:
We've updated the boot switch image above to correctly reflect the switch positions for the BitsyX. Further detail can be found in Revision B of the CE Developer's Getting Started Guide