for people that have made pandora and magic mem stick and tried to downgrade their slim but nothing shows up or works but it works on a phat its because you need extra files to install CFW on the slim.
1. download despertar del cementerio V4 from here:
http://dl.qj.net/Despertar-del-Cementerio-v4-PSP/pg/12/fid/15741/catid/114..this will install 3.80 M33-5 straight onto your slim btw.
2. put these files in your PSP > GAME folder on your magic mem stick.
3. use a CFW psp and go to over to your XMB menu and go to game > memory stick, run the file named "Despertar del cementerio V4".
4. accept and this will write neccessary files to your magic mem stick. put the magic mem and pandora in your psp slim, wait and a menu should show up as screen support has been added. press X to install the CFW...wait till its done and your finished!