Here, you might need the extended pandora boot menu.
I will find a link in a bit and edit when I find it so keep checking....... Found it! You need Boosters Multi-IPL Loader.
http://forums.maxconsole.net/attachment.php?attachmentid=17139&d=1189513822 (hopefully you have an account there)
DO NOT PUT THIS ON THE MMS, INSTEAD PUT IT ON ANOTHER MS (or you COULD write it on the mms then use the pandoras battery creator and convert the battery to normal)
This only works if your slim is 3.90 or higher (I hope it is)
1. d/l it
2.Double click "install.cmd" (you need Windows XP)
3.Connect MsProDuo to PC via USB.
4.press 'Y' key to "Are You Sure ?[Y]" message.
5.Disconnect MsProDuo after few seconds.
Im in a hurry so, if you are confused reply fast...