Go into airplane mode in minimal boot mode.

import android.widget.TextView;

import com.android.internal.telephony.ITelephony;

import com.android.internal.telephony.Phone;

import java.util.List;

                | StatusBarManager.DISABLE_HOME

                | StatusBarManager.DISABLE_RECENT);

        setAirplaneModeIfNecessary();

        mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);

        // Check for (and recover) retained instance data

        final Object lastInstance = getLastNonConfigurationInstance();

        return false;

    }

    /**

     * Set airplane mode on the device if it isn't an LTE device.

     * Full story: In minimal boot mode, we cannot save any state. In particular, we cannot save

     * any incoming SMS's. So SMSs that are received here will be silently dropped to the floor.

     * That is bad. Also, we cannot receive any telephone calls in this state. So to avoid

     * both these problems, we turn the radio off. However, on certain networks turning on and

     * off the radio takes a long time. In such cases, we are better off leaving the radio

     * running so the latency of an E911 call is short.

     * The behavior after this is:

     * 1. Emergency dialing: the emergency dialer has logic to force the device out of

     *    airplane mode and restart the radio.

     * 2. Full boot: we read the persistent settings from the previous boot and restore the

     *    radio to whatever it was before it restarted. This also happens when rebooting a

     *    phone that has no encryption.

     */

    private final void setAirplaneModeIfNecessary() {

        final boolean isLteDevice =

                TelephonyManager.getDefault().getLteOnCdmaMode() == Phone.LTE_ON_CDMA_TRUE;

        if (!isLteDevice) {

            Log.d(TAG, "Going into airplane mode.");

            final Intent intent = new Intent(Intent.ACTION_AIRPLANE_MODE_CHANGED);

            intent.putExtra("state", true);

            sendBroadcast(intent);

        }

    }

    /**

     * Code to update the state of, and handle clicks from, the "Emergency call" button.

     *