James @j_duffy01 from twitter just recently publish activateBX (experimental internal project ) that allows changing any serial number to custom serial number with checkra1n jailbreak. On his videos, we can clearly see the iPhone X with a custom serial number.
activationBX live demonstration
ACTIVATEBX CAN CHANGE ANY IPHONE SERIAL NUMBER WITH A CUSTOM OR NEW SERIAL (CHECKRA1N) and Activate.
since the release of Checkra1n, the world’s first jailbreak for devices running Apple’s iOS 13 using bootroom exploit. Because jailbreaks are so powerful and by definition disable a host of protections built into the OS, many people have rightly been tried Checkra1n with a particular emphasis on security.
For what we understand the device can be completely activated and basically everything works normally. also we can see @j_duffy01 using sim card to make a call and browsing the device on 3G connection.
activateBX can change any iPhone serial number with a custom new serial, it needs to be jailbreak first with checkra1n. Sim and calls seams to work and looks everything works after restart the device. This amazing Serial number modification is released this could be a Headache to apple, maybe will force apple to fix this exploit.
More about icloud bypass projects
Demystifying iCloud/Activation Bypass Utilities