Firmware Update fill Memory-How to dump?

Hello! I have  2GB Sansa clip. Before the update I had 12 albums and 2 language lessons with room for more. I installed the update and it took up all the memory. I know only have 5 1/2 albums and its maxed out. How do I dump this update and go back to the original setting? I much rather have the room than this update. Thanks in advance for your kind help. 

Thank you Miikerman. I pulled the music off and reformatted which corrected the memory issue. Thanks again for your help.