The error literally tells you what to do. libusb is a library that allows software to talk to USB devices.
If you are trying to restore an older, unsigned iOS version (e.g., going back to iOS 17 from iOS 18 after Apple stopped signing iOS 17):
An outdated tool will send malformed requests to registration servers. Download the absolute latest version of 3uTools, iTunes, or your specific jailbreak installer. Turn off any antivirus programs or firewalls temporarily, as they can block the server communication required to register the ECID. Summary Checklist Gets the exact 64-bit unique ID from iTunes or 3uTools. Server Whitelisting Registers the ID on the developer's server database. DFU Mode
The phrase " ECID not registered " typically appears in the context of iOS jailbreaking custom firmware installation (such as using tools like ecid not registered install
Verify target device and files
An outdated version of your installation software may not be able to ping the registration server correctly.
If you are simply trying to restore standard firmware via iTunes and see registration-related errors: The error literally tells you what to do
Use tools like iMazing or TSS Saver to save blobs automatically whenever Apple is signing a new iOS version.
This is more subtle and refers to a different step in the process. While sideloading apps (e.g., using AltStore or Sideloadly) doesn't directly use your ECID, it relies on a related unique identifier called the UDID (Unique Device Identifier).
Many of these tools require a specific "Pwned DFU Mode," which is a special, exploitable state. Your device may be in standard DFU or Recovery Mode, which is not enough. A common mistake is pressing the wrong buttons or holding them for the wrong amount of time, especially on newer iPhones without a physical Home button. Download the absolute latest version of 3uTools, iTunes,
Select the correct options matching your current project (e.g., Bypass, Jailbreak, or TrollStore).
Bypasses system blocks so the tool can read the hardware ID.
ECID Not Registered During Installation 窶� Request for Assistance
If you are getting this error while trying to downgrade to an older iOS version, you cannot bypass it without previously saved SHSH2 blobs matching your specific ECID.
For the vast majority of users, the solution is to stop fighting the IPSW file and check your beta enrollment status, or accept that the software version you are trying to install is no longer supported by Apple's servers. The fingerprint of your device is valid; it is simply the paperwork for the installation that is out of date.