[mothered]

You are able to jailbreak and iPhone and change the IMEI that way.

The IMEI number Is dedicated to the device It's assigned to, hence spoofing/changing It may be rejected by the carrier during the activation process.

That said, there Is a workaround. The first 8 digits of the IMEI number known as the TAC (Type Allocation Code) Is what Identifies the model & device manufacturer. When changing It, leave those digits as Is and spoof the rest. As such, the IMEI number will show up to It's corresponding device when activating.