black_sheep, If you extract your firmware with s1fwx
HERE you will be able to open it with s1res
HERE , You will find 2 entries within your firmware LOGO.RES which is your startup animation and END.RES which is your shutdown animation. You can use s1res to import new images into your firmware, save it then load it back to your player using the MP3 Player Upgrade Tool. You will find guides to using all these apps in the Knowledge Base
HERE