Motorola V400
Start up tone
If you connect your computer to your phone with a data cable and you download "Motorola Product Support Tools" you can use this program to get into the system files and replace the Start~up and/or Power~down file. All audio sounds must be in .mp3 format (do not include the extension .mp3) and must be named exactly as stated (uppercase S for Start-up and uppercase P for Power-down).
These files can be found under the directory:
/a/mobile/audio/
Hope this answers your question.