Zte MF29A User Manual page 38

If you select Modify, the modification parameters are shown in the following figure:
Type the old PIN code, and then type two times the new PIN code. Click Apply to
confirm your configuration.
NOTE: Three times consecutive wrong PIN code entries will block the (U)SIM card.
To unlock it, you need the PUK code. The PIN code and PUK code may be offered
together with the (U)SIM Card. If not, please contact with network operator.
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