Te recomiendo este hilo en xda developers, esta en inglés pero está bastante claro el como hacerlo.. un saludo.
http://forum.xda-developers.com/showthread.php?t=1852309 [nofollow]Here was an example of how to find your device ID:
DEVICE ID AND UNLOCK KEY
To unlock your device, you need to retrieve your device ID and obtain an unlock code.
I. Retrieving your device ID
Put your device in fastboot mode (Power+Vol Down) and connect over USB
Open a command prompt or Terminal session
Go to the Directory where you installed the Android SDK tools, and type: $ fastboot oem get_unlock_data This fastboot command will return a character string. This is the Device ID which you will be using to generate your unique unlock key. $ fastboot oem get_unlock_data
(bootloader) 0A40040192024205#4C4D3556313230
(bootloader) 30373731363031303332323239#BD00
(bootloader) 8A672BA4746C2CE02328A2AC0C39F95
(bootloader) 1A3E5#1F53280002000000000000000
(bootloader) 0000000
OKAY
[0.297s]
To generate your unlock code, you’ll need to paste together the 5 lines of output into one contnuous string without "(bootloader)" or white spaces.. Using the example above, the line you’d send us would be:0A40040192024205#4C4D35563132303037373136303130333 2323239#BD008A672BA4746C2CE02328A2AC0C39F951A3E5#1 F532800020000000000000000000000
La web de MOTOROLA también te explica como hacerlo:
https://motorola-global-portal.custhelp.com/app/standalone/bootloader/unlock-your-device-a [nofollow]