Need Help with PSP slim running 3.90 M33-3

[MrE]

I just upgraded to a PSP slim and used my Pandora's Battery to first install 3.80 M33-5 and then upgrade to 3.90 M33-3.  The problem I am having is that now I can't boot up the ISOs that work fine in my PSP phat.  What am I doing wrong?  Sorry for being such a n00b.  I was all excited to upgrade from phat to slim and now I'm a little bummed...

 

UPDATE:  I'm such a retard!  I forgot I needed to resetup my configuration so it doesn't boot from UMD.  Sorry guys...