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How to use NFC on the Galaxy S3 I9300 even if phone screen is locked

October 25, 2012

The Samsung Galaxy S3 GT-I9300 has an embedded NFC chip that allows you to share files to another NFC-capable device. Aside from sharing files, you can also pay your bills and launch certain phone functions and apps instantly through NFC tags. But, for you to use this feature, you will need to unlock your phone’s screen first to activate NFC. This can be an inconvenience if you’re in a hurry and you don’t have the time to unlock your phone.

XDA Developers member mayhemer offers a convenient solution by creating a hack/mod that allows you activate NFC without unlocking your phone’s screen. The hack/mod has two flavors: one that allows you to enable NFC even if the screen is locked (provided that the screen is on), and the other that activates NFC even if the phone is asleep or on standby (even if the screen is off).

The mod/hack can be useful when you have NFC tags in your car, on office desks, and in the bedroom and you don’t want to have to unlock our phone to activate NFC. You can also instantly share files even if the phone’s screen is off or locked.

But, you will need to be careful, though. Flashing this mod could potentially open the gates of unrestricted data transfer, including malicious hacks and viruses reaching your phone. Make sure not to leave your phone unattended; or, put it somewhere where no one can easily access your phone. NFC chips need to be close in order to communicate.

This guide shows you how to use NFC on the Galaxy S3 I9300 even if phone screen is locked.


  • The instructions in this guide are intended for use with the Samsung Galaxy S3, model number GT-I9300. Applying these instructions on another device or model may produce undesired outcomes.
  • The mod described in this guide has been observed to be incompatible with CyanogenMod 9 (CM9).  This may also be incompatible with CM9 derivatives.
  • The information in this guide is provided for instructional and educational purposes only. There is no guarantee that these instructions will work under your specific and unique circumstances.
  • Use these instructions at your own risk. We shall not hold any responsibility or liability for whatever happens to you or your device arising from your use of the info in this guide.
  • Read and understand the whole guide first before actually performing the instructions.



  1. Deactivate NFC on your phone.  This can be done by unticking “NFC” from Settings > More Settings.
  2. Copy the NFC mod file to your phone’s internal SD card.
  3. Backup your original NFC app.  You can use a file manager app for backing it up.  The file you need to back up is /system/app/Nfc.apk.  If /system/app/Nfc.odex also exists, back that up, too.
  4. Turn off your phone.
  5. Boot into ClockworkMod Recovery.  Press Volume Up, Home, and Power until ClockworkMod Recovery boots.
  6. Make a NANDroid backup of your ROM.  You can do this by selecting Backup and Restore > Backup in recovery.
  7. Select Install ZIP from SD card > Choose ZIP from SD card.  Locate the NFC mod file, select it, and confirm that you want to flash it.  Installation shouldn’t take more than a minute.
  8. Return to main recovery menu.
  9. Select Advanced > Wipe Dalvik cache and confirm the action on the next screen.
  10. Return to main recovery menu.
  11. Select Reboot system now to restart your phone.
  12. Once the phone has rebooted, reactivate NFC on your phone.  This can be done by ticking “NFC” from Settings > More Settings.

Congratulations! You can now use NFC even if your phone screen is locked.