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If the iPhone is locked and you are able to unlock it in any way, without passcode or Siri, you can try the following ways to unlock it:
Solution 1: Unlock iPhone without Siri or Passcode or iTunes by iPhone Passcode Tuner
Solution 2: Get into a Locked iPhone without Siri or Passcode via Synced iTunes
Solution 3: Bypass iPhone Screen Passcode without Siri Using iCloud