Ecid Check Iphone Serial Number -

If you have ever tried to jailbreak an iPhone, downgrade iOS, or troubleshoot a bricked device, you have likely stumbled across a cryptic string of characters called the (Exclusive Chip ID). Alongside it, you’ve probably been asked for your iPhone’s Serial Number . But what exactly is the relationship between these two identifiers? Why do tools like iTunes, pwned DFU mode, and iOS firmware checkers constantly request an "ECID check iPhone serial number" lookup?