Are you curious about what IMEI stands for? Do you want to learn how to interpret the parts of IMEI numbers to learn more about a device? XDA Senior Member xsenman has written a guide to IMEI numbers that aims to explain all this, along with details on how to preserve them on your phone during ROM flashes.
IMEI stands for “International Mobile Equipment Identity,” and is a 15 digit number that uniquely identifies each mobile phone. Because they are unique, they can be used to track a stolen phone, or block carrier access to any device. It is illegal to change it in most regions, so preserving your IMEI number is extremely important.
While the area that the IMEI number is stored on is protected on most phones, many Samsung devices have it saved on the EFS partition, which is easily accessible with a rooted phone. That’s why there are chances that while flashing a ROM to your device, you might end up messing up the EFS partition and thus losing your IMEI number.
For more information on IMEI numbers, a complete description of what their digits stand for, and details on how to preserve them on your phone, head over to the forum thread. The thread also links to validators for checking if an IMEI number is valid or blacklisted, and a couple of other useful threads that guide you with fixes to EFS-related problems that can effect your IMEI number._________