Mo DeLonge, The safest way to theme your player is to modify your own firmware which is quite easily done with s1res. Details on how to do this are in the Knowledge Base Section. If you find a theme you like and it is already in a firware you can extract the images with s1res and then load them into your own firmware.

To see the version details connect your player and open the MP3 Player Upgrade Tool you will see the details of your current installed firmware on the left. If you select your upgrade firmware its details will be displayed on the right.

Be aware though that there can be variations of the same version firmware. If your player has 3.5.35 just because another firmware is also 3.5.35 does not mean it is compatible with your player.

Re: Firmware & Themes
 

tadad!
So if my firmware ends up failing, i just have to experiment with different firmwares until i get the right one, right? :?

Mo DeLonge,
If your firmware fails just use your backup.

If you are theming your own dump.bin you will not have any problems unless you lose power or pull the cable during update your own firmware will not cause you any problems.

If you are using someone elses themed firmware you run the risk of killing your player. It depends on how incompatible the other firmware is you could recover just by reloading your backup or you could kill it completely and have to do a DEAD PLAYER RECOVERY.