Boot telecommands direct the boot operations of either the SIU or EPU primary boot code. When the SIU is in Boot Mode, the boot commands directed to an EPU are not valid and will not be executed. When the SIU is in operational mode, the Boot commands must be directed to an EPU. Under these circumstances, the Boot commands will be forwarded to the selected EPU and processed by that EPU. An EPU will only process a boot command while it is in the Boot Mode.

Boot Telecommand Function Codes
APID	Function Code	Description
0x640	0	Boot Start. Removes the primary boot code from the initial timeout and allows further operational telecommands or file uploads for the primary boot code to take place.
	1	Boot Reset. Forces a reset of the primary boot code into a known restart state.
	2	Boot Error Dump. Dumps the value of a queued error word by the primary boot code.
	3	Boot RTOS Execute. Begins execution of an RTOS image and the second-stage boot process.