The hourglass is in the BREC. Changing it to another 20x36 image is all that you can do with it. If you want to do that, then do a lot of reading at s1mp3.org and study the hardware in detail, know basic Asm programming and using a hex editor, etc.
http://wiki.s1mp3.org/BREC#The_Hourglass
What player version (CPU, board ID, etc.) do you have, which works?