When enabled, the PIN is required to activate the SIM card ... simply find the packaging and enter the provided PUK code. Unlock the SIM Card without a PUK code However, if you lose the SIM ...

[Jason Gin] wanted to reuse the SIM card that came with a ZTE WF721 ... he was able to work his way backwards and determine the unlock command and its PIN code. It turns out the PIN was even ...

A PUK code is required if a GSM SIM card was locked after entering the wrong PIN code three times in a row. Entering a wrong PUK code ten times in a row disables the SIM card permanently.