To enable debug flags of ril, mms, network in runtime:

1. chmod +x enable_debug_flags.sh
2. ./enable_debug_flags.sh
3. Wait for B2G restarting complete.
4. Capturing main logcat by adb logcat -v threadtime > logcat.txt
5. Capturing radio logcat by adb logcat -v threadtime -b radio > logcat_radio.txt

Note: network flag can be enabled at runtime since b2g 2.0.

To capture the packets in the devices.

1. Install attached tcpdump command into test device:

   adb remount; adb push tcpdump system/bin/;adb shell chmod 777 /system/bin/tcpdump

2. Start capturing tcpdump:

   adb shell tcpdump -i any -p -s 0 -w /data/capture.pcap

3. Backup tcpdump result:

   adb pull /data/capture.pcap .