PUK2

PUK2, or Personal Unblocking Key 2, is a security code used on some SIM cards to unblock PIN2 after it has been locked due to too many incorrect PIN2 entries. PIN2 is a separate code from the standard PIN (PIN1) and may be required for certain SIM features such as fixed dialing, operator-specific services, or advanced SIM toolkit functions. Not all SIMs implement PIN2 or PUK2, and the exact behavior can vary by carrier and device.

If PIN2 is blocked, attempting to enter it incorrectly several times will prompt for the PUK2. Entering the correct PUK2 allows the user to set a new PIN2. After successfully unblocking, the new PIN2 must be entered to regain access to the associated features. If the PUK2 is entered incorrectly too many times (the exact limit varies by system), the SIM can become permanently blocked, necessitating a replacement SIM card.

PUK2 codes are typically 8 digits, but the length can vary by issuer. The PUK2 is usually provided by the mobile operator or found on the SIM card’s packaging or documentation. In some cases, it may be accessible via the operator’s online account portal or customer support, especially when the physical card or documentation is not available.

Security note: PUK2 should be kept secure and not shared, as it can unlock access to protected SIM features. If PUK2 is lost or unknown, contact the mobile carrier for assistance. See also PIN1/PUK1 and PIN2 for related concepts.