A factory reset does not unlock the phone

Erase wipes your data. The carrier lock and the account lock stay.

1. 01

   Back up first. A reset deletes photos, messages, and apps that are only on the phone.

2. 02

   iPhone: Settings → General → Transfer or Reset iPhone → Erase All Content and Settings. Android: Settings → System → Reset options.

3. 03

   When it starts again, a carrier lock still shows up as a SIM warning. An Apple ID or Google account still asks for the old login.

4. 04

   Reset because you are selling a phone you can already sign into. Do not reset because a forum said it clears a network lock.

Official carrier and settings procedures only. This is not a bypass, IMEI, or stolen-phone service.