What is ECID of an iPhone
If you are a new user of iPhone and wish to be in the area of unlocking or jailbreaking the iPhone, you must be aware of the ECID which is the short form of Exclusive Chip ID. The ECID is unique for each iPhone and it looks something like
00000XXXXXXXXXXX in hexadecimal format
Here are some more technical details about the ECID which will help you understand the importance of the ECID. When you are using the iTunes for the restore process it contacts the Apple server for which generates a unique signature for that particular iPhone. You must have this signature recorded before a new version is available.
ECID is also a sort of new security element from Apple. Apple sends a signed information based upon the ECID of your phone.
The 3GS iPhone has slightly changed security which means that its hardware stops iPhone software from being useful unless you have received the signed confirmation based upon the ECID. The iPhone will reject the new Iphone Software ( also called IPSW) if the signature is not valid.
If the signature does not match, it will flag it as a Custom Iphone Software ( IPSW) and may flag an error before flashing ( or programming) it to the iPhone. The term flashing here means storing it in the flash memory of the iPhone.
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