Red screen of death on PSP?

I have psp,it show the blue screen of death,so i press o, then blue screen start agian how can i passed it?

• i have psp with 3.52 m33 4,using the recovery menu i format flash 0,then the my psp couldnt start,i take it to a man and he only install 1.50 but the blue screen of death appear ,when i press o the memory stick light turn on, the screen became black and return to blue screen of death ,i can play umd but i can access xpm and recovery mode please help me !

• Answer:

  you dont format flash0.. that erases flash0.. format flash1 is ok. you need to install a custom firmware. he used a pandora battery and unbricked it, but the unbricker doesnt install a full 1.5, it installs a shell of 1.5.