Brewology

I was trying to install a XMB and the my psp(slim) and then when i re start theres only a black screen and then just shut-off

any one can help me TT_TT

Try starting in recovery mode and then restoring your flash0 with the backup you hopfully made, If not the only other way to unbrick is with pandora' s

Thx now i only need another psp

What custom firmware do you have? You could always check the internet for a flash0 dump of your firmware, that would probably be easier then manually making a pandora's battery or finding another psp to do it the software way. Also, I have noticed a lot of people semi-bricking recently just because of trying to flash their flash0. Really, if you have an updated cfw and wanted a custom xmb theme just use the ones made for that firmware that you access from the theme menu (I forgot what their technical name is). Do you know if the theme was actually made for your firmware version?