How to Write to the Android File System

1. Download and install the Android SDK from the Android Developer website.

2. Unlock your Android device and press the Home button. Press the Menu button and touch 'Settings.' Tap 'Applications,' then 'Development.' Touch the box next to 'USB Debugging.' Press the Back button to exit the Settings menu. Connect your Android device to your computer with a USB cable.

3. Click 'Start' then type 'Cmd' in the search box and press Enter. Type: 'cd C:\Program Files\Android\android-sdk\platform-tools' and press Enter.

4. Type 'adb install' followed by the location of the Android application on your computer and press Enter. This will write an Android APK file to the Android file system. Type 'adb push' then the location of the file on your computer and the location on the Android file system where you want to write the file. For example: 'adb push c:\update.zip /root/update.zip.' Press Enter.