The SIM card on your mobile phone will become locked if you enter an incorrect personal identification number (PIN) three times. To unlock it you must reset your PIN by entering your SIM card's unique unlock key (also called a PIN unblocking key or PUK).
If you're willing to unlock the phone on your own, here's what you need to know. And carriers such as T-Mobile offer apps that unlock phones. Before you unlock your phone, though, make sure it's compatible with the new carrier's network. Verizon and Sprint use a standard called CDMA, and AT&T and T-Mobile use GSM.
To find the SIM PIN / PUK numbers for your 4G LTE SIM card
Tap or click My PIN and Unblocking Key (PUK) under "About My Device". Your default PIN and PUK will be displayed in a pop-up window.Essentially, SIM lock requires your lock screen PIN, pattern, password, or fingerprint and SIM card to be in place before the phone can be unlocked. You can kind of think of it as physical two-factor authentication, which deters thieves from removing the SIM in order to avoid being tracked.
Unlock your mobile using PUK code
- Enter any PIN into your mobile handset, eg. 0000.
- Press [OK] or [YES]
- Repeat until your phone asks you to "Enter PUK"
- Retrieve your PUK code by entering your details below:
Find your PUK on the SIM card pack
If you've still got the little pack that the SIM came in, check on the credit-card sized bit of plastic that the SIM snapped out from. The PUK Code is an eight digit number, and is usually printed on the back.To get your PUK number:
- Dial *100*8# from another phone.
- Enter your mobile phone number.
- Enter your national ID number.
- You'll receive your PUK code shortly via a text message.
A PUK code stands for “Personal Unlock Key.” It's a unique code that is linked to your mobile phone's SIM card and is usually 8 digits long. You will need the PUK code if you have set a SIM Card lock and entered the wrong passcode 3 times. Your phone will become locked, and you will need the PUK code to unlock it.
First, go to Settings in your Android device's main menu. In the Settings menu, choose Security, then Set up SIM card lock. First, here's how to disable the SIM card PIN. All you have to do is to uncheck the box next to “Lock SIM card” and then confirm the change by inputting the current PIN code.
Unblocking your phone
Your phone can become blocked if you enter the wrong SIM card PIN number three times in a row. To unblock your SIM you'll need a PUK (Personal Unblocking Key) code. Remember that unblocking is different to unlocking.Turn off your mobile handset, and remove the SIM card. Wait two minutes and then put the SIM card back in. Turn your handset back on and allow it to reboot. If you see an error message like “SIM Card Rejected”, this means that a PUK has been entered incorrectly more than 10 times, and the SIM card has been wiped.
The PUK (Personal Unblocking Key) code is a code consisting of 8 digits that you also received with your SIM card. It is used to unblock your SIM card when you entered 3 times a wrong PIN code. These codes are provided with the SIM card in the Welcome Pack.
The SIM Card can be blocked easily in the My Vodafone Self Care in the menu Settings of services - Blocking. You can also call the Customer Care line *77 (800 77 00 77) or visit one of Vodafone stores. To block the SIM, you have to know the user password. We will block your SIM Card within 60 minutes of your request.
How to Fix a Blocked PUK
- Take the battery cover off of the blocked phone and remove the battery.
- Write down the phone's IMEI and SIM card number.
- Put the phone back together and power it on.
- Call your wireless provider from another phone and ask to speak with someone about PUK unlocking.
4 Get into A Locked iPhone with iTunes (Erase Data)
- Open iTunes on your PC. Connect your iPhone to your computer.
- When iTunes recognize your iPhone. It will start to sync and back up your iPhone.
- Then click “Restore” on the pop up window. This would reset your device.
Resetting SIM card through the phone's settings
Insert the SIM card into your cell phone's SIM card slot and place the back cover securely. Then, turn on the phone. Step 2. Go to the "Settings" menu and choose "Reset" from the list of options that are displayed.