adb shell
stop b2g
cd /data/b2g/mozilla/*.default/
echo 'user_pref("devtools.debugger.prompt-connection", false);' >> prefs.js
start b2g
adb shell
stop b2g
cd /data/b2g/mozilla/*.default/
echo 'user_pref("devtools.debugger.prompt-connection", false);' >> prefs.js
start b2g