USBWatchdog is an Android service which monitors the property
usbwatchdog.heartbeat and reboots the device if the value does not
change in a specified interval. USBWatchdog is intended to help
recover a lost USB connection from a host computer in the event the
host loses the ability to communicate with the device over USB.
Android 2.3+
The USBWatchdog repository contains an Android Studio 2.0 beta project
which can easily be built using Android Studio 2.0
beta. Choosing the
Build->Build APK menu options from Android Studio will create a
debug version of the app in
USBWatchdog/app/build/outputs/apk/app-debug.apk.
USBWatchdog requires a rooted device which either has the su command
available or which allows apps to be installed to /system/app.
Download a pre-built debug version of USBWatchdog.apk or build your own.
adb install -r USBWatchdog.apk
Installing USBWatchdog as a system app varies depending on how your device is rooted. The following will work on a device which can run adbd as root and which can remount /system using adb remount.
# Restart adbd as root.
adb root
# Make /system writable
adb remount
adb push USBWatchdog.apk /data/local/tmp/
adb shell dd if=/data/local/USBWatchdog.apk of=/system/app/USBWatchdog.apk
adb reboot
USBWatchdog works in combination with a program running on the host
computer which periodically updates the usbwatchdog.heartbeat
property on the device. If usbwatchdog.heartbeat is not empty and has
not changed since the last time USBWatchdog polled the property's value,
then the device will log the time and reason to the file
/data/data/com.mozilla.autophone.usbwatchdog/files/usbwatchdog.log
and will reboot.
The host computer program should update the usbwatchdog.heartbeat
property more frequently than the USBWatchdog service polls the value.
USBWatchdog is started on the device via the command:
adb shell am startservice \
-n com.mozilla.autophone.usbwatchdog/.USBService \
[--ei poll_interval <seconds>] [--esn debug]
--ei poll_interval <seconds>
specifies the time period between checks to see if the
usbwatchdog.heartbeat property has changed. If the
usbwatchdog.heartbeat property is not empty and has not
changed within the interval, the device will reboot.
--esn debug
enables additional debugging output to logcat.
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