Hey guys, i have my psp-1000 and a friend's hacked one (also 1000). I followed the guide called "how to downgrade your psp and upgrade to custom firmware"
-http://www.makeuseof.com/tag/how-to-downgrade-your-psp-upgrade-to-a-custom-firmware-part-two/

Because my PSP is version 6.31 OFW, i used part two.
So it's all going fine, i installed the DDC or whatever MMS, the elf menu and nand tool, and pandorized the battery. Now i take the new mms- it's an 8gb Pro Duo- and put it in my psp. Then i put in the battery. So the green light automatically comes on, but the screen stays black. I feared a brick. So i put in my friend's non-Pandora battery and my PSP works perfectly, so it's not bricked. But now i need to know how to use the darn battery and MMS!! I just want to play homebrew and downloaded games.

Please can you give me a solution that doesn't involve hardmodding my psp battery. In the meantime i have un-pandorized it on my friends psp. I did the whole format and repartition beforehand. I tried holding down L when putting the battery in, etc. but to no avail.

Thanks in advance, guys!

P.S. I should mention that my battery is genuine- the Li ion or something, came with the PSP in a sony shop