Editing Functionality of Host Card Emulation in Android

by

Ok ! So i’ve found a solution to the problem I was having!

On the Nexus 7, when the NFC is turned on, it gets its information from a config file in “/etc/” called “libnfc-brcm-20791b05.conf”

Inside of this file there is a parameter called “NFA_DM_START_UP_CFG”

By default, it looks like this:

NFA_DM_START_UP_CFG={42:CB:01:01:A5:01:01:CA:14:00:00:00:00:0E:C0:D4:01:00:0F:00:00:00:00:C0:C6:2D:00:14:0A:B5:03:01:02:FF:80:01:01:C9:03:03:0F:AB:5B:01:00:B2:04:E8:03:00:00:CF:02:02:08:B1:06:00:20:00:00:00:12:C2:02:01:C8}

To edit the UID that is generated at Emulation, you need to add some bytes to the end of this parameter.

The first byte you add is 0x33 (This means that you are going to manually set the UID)

The second byte that is added is the length of the UID you wish to set (This can be either 4,7 or 10 bytes, so this second byte can be 0x04, 0x07 or 0x0A)

The next bytes are then the ID you wish to set! (NOTE: Depending on how many Bytes you add, you should change the first byte of the array to reflect the new size of the array – it starts at 42, so if you were to add 6 bytes it should change to 48)

For example, if you wished to set a 7 byte ID of 01 02 03 04 05 06 07, the new config line would look like this:

NFA_DM_START_UP_CFG={4B:CB:01:01:A5:01:01:CA:14:00:00:00:00:0E:C0:D4:01:00:0F:00:00:00:00:C0:C6:2D:00:14:0A:B5:03:01:02:FF:80:01:01:C9:03:03:0F:AB:5B:01:00:B2:04:E8:03:00:00:CF:02:02:08:B1:06:00:20:00:00:00:12:C2:02:01:C8:33:07:01:02:03:04:05:06:07}

You can then push this config file to your nexus device using adb:

-> adb root
-> adb remount
-> adb push libnfc-brcm-20791b05.conf /etc/
-> adb reboot

This will reset the Nexus with the new config file in, and upon emulation the UID will now be set to 01 02 03 04 05 06 07

Hope this helps anyone reading my question!

More Related Contents:

  1. Get Static NFC Tag Id with HCE mode
  2. Emulate Mifare card with Android 4.4
  3. Host-based Card Emulation with Fixed Card ID
  4. How to find serial number of Android device?
  5. Android app enable NFC only for one Activity
  6. Bluetooth pairing without user confirmation
  7. Android: How to programmatically access the device serial number shown in the AVD manager (API Version 8)
  8. Getting started with Open NFC emulator
  9. Get NFC tag with NDEF Android Application Record (AAR)
  10. Android: Changing NFC settings (on/off) programmatically
  11. How to prevent NFC tag cloning?
  12. Same serial number on several android devices. Adb is useless. How can I change the serial number?
  13. Android Unique Serial Number
  14. Secure element Access Control on ICS 4.0.4
  15. Sending and Receiving SMS and MMS in Android (pre Kit Kat Android 4.4)
  16. How do I get the web page contents from a WebView?
  17. Send text to specific contact programmatically (whatsapp)
  18. Quality problems when resizing an image at runtime
  19. How do I order my SQLITE database in descending order, for an android app?
  20. SurfaceView flashes black on load
  21. Render error in Android Studio 3.0 Layout Editor
  22. Is there any way to give everyone access to firestore database, but only via app?
  23. Crop video before encoding with MediaCodec for Grafika’s “Continuous Capture” Activity
  24. How to play multiple video files simultaneously in one layout side by side in different view in Android
  25. How to execute a method by clicking a notification
  26. Android LinearLayout with color resource: What am I doing wrong?
  27. Should use “sp” instead of “dp” for text sizes
  28. Run Button is Disabled in Android Studio
  29. How to set the app icon as the notification icon in the notification drawer
  30. Crop an Image by passing the image file path in Android

Leave a Comment