boot_usb was designed to communicate with the bootloader of EZX phones. It is
part of the OpenEZX project (http://www.openezx.org/) and only usefull for
Motorola EZX linux phones.

This program allows you to download an execute code on the phone ram.

It allows you to test a kernel zImage without flashing it into your phone. You
need to enter the bootloader mode of the EZX phone before the program can
communicate with the phone:

A780:		press camera and jogdial(scrollwheel) button while power on.
E680(i): 	press camera and volume down button while power on.
ROKR E2: 	press the camera button while power on.
A1200: 		press voicedial button while power on.

A780/E680 presents a blue screen with white text on it and ROKR E2/A1200
presents red screen with black text on it in bootloader mode.

If your EZX phone is not listed here you have perhaps more luck on our wiki:

http://wiki.openezx.org/Bootloader