Forwarded Call Alert is using the internal Android log (radio logcat) to determine if an incoming call is redirected. To access that buffer, the READ_LOGS permission is required.

With the release of Android 4.1 "Jelly Bean", Google silently changed how the READ_LOGS permission works.

Before, the user was made aware of READ_LOGS when installing the application. Now, the permission is ignored by Android. Instead, it is only accessible to developers with rooted phones - for security reasons. All other apps can only read their own logs - with no access possible to the radio log.

Variant A: ROOT the phone (dangerous)

When Forwarded Call Alert is started on Jelly Bean, it attempts to grant itself the required permission (pm grant de.duenndns.forwardedcall android.permission.READ_LOGS) using ROOT. If that works, you can use the app normally.

Variant B: Install the Android SDK (complicated)

This is a short mini-HOWTO for manually enabling Forwarded Call Alert on your non-rooted Android 4.1+ phone:

  1. PC: Download the Android SDK Tools.

  2. Smartphone: Android 4.2+: Restore the "Developer Options" menu.

  3. Smartphone: Enable USB Debugging: Android Settings -> Developer options -> Android debugging (USB).

  4. PC (optional): Install the required USB drivers for your phone.

  5. PC: Locate the adb (or adb.exe) command, and run it as follows:

    adb shell pm grant de.duenndns.forwardedcall android.permission.READ_LOGS

    The correct command for the free version of the app is:

    adb shell pm grant de.duenndns.forwardedcall.free android.permission.READ_LOGS

    The command should have the following output, and then return almost immediately:

    * daemon not running. starting it now on port 5037 *
    * daemon started successfully *

    If you see an error message, the app is not properly installed or you used the wrong command line (free vs. full). If you see "- waiting for device -", please check that you a) enabled USB debugging, b) installed the correct USB driver and c) connected the device via USB to your PC.

  6. Smartphone: Disable USB Debugging: Android Settings -> Developer options -> Android debugging (USB).

  7. Have fun!

You can star the Android bug to improve the situation. However, please refer from writing a "me too" comment there.