Changing Start-up & Power-Down Sounds:
To modify the Startup and Shutdown sounds you must:
1. Modify ONLY the seem 0032_0001 > offset 24 > bit 3 enabled (Checked)
2. Be sure to set the pad volume not to 0. Reboot and you should hear the usual startup sound.
3. Create 2 mp3 files (4/5 seconds long or else the mobile will chop'em automatically) and rename them into:
-----> Cust_Start~up.mp3 for startup.
-----> Power~down.mp3 for shutdown.
4. Copy these files under /a/mobile/system or /c/mobile/system depending on your firmware version[thx to bayliss#21].
5. Shut-off and then on again and it's done!

Changing the Start-up & Power-Down Animations:
First you need to turn off the Motorola OEM Startup/Shutdown animation.

1. The moto startup is in 0032_0001.seem at offset 1D, bit #3. (1 on, 0 off)
2. The moto shutdown is in 0032_0001.seem at offset 31, bit #0. (1 on, 0 off)

Next you need to turn on the Custom Startup/Shutdown animation.

3. The custom startup is in 004a_0001.seem at offset 23. Set this offset to "01" to turn it on.
4. The custom shutdown is in 0032_0001.seem at offset 46, bit #0. (1 on, 0 off)
5. When custom startup and shutdown is activated, your phone looks in seems 0206_0001, 0207_0001, 0208_0001, and 0209_0001 for the name of the animated gif to display. 0206 and 0208 are for startup and 0207 and 0209 are for shutdown. These will usually already have the right filenames in them.
6. So although you dont really need to check the 0207 & 0209 Seems If you have problems, take a look at them , but most likely the files already have "/(a or c)/custwakeup.gif" and "/(a or c)/custgoodbye.gif" written in them.
7. Now that the seems are in order, Make some animated GIFs that are 176x220 pixels and upload them to your phone to replace the old ones.
8. Restart your phone through P2Kman and then power cycle (Switch off & then switch on) your phone to see your new Start-Up And/or Shut-Down Animations in action