Well heres the link:
This is basicly that thing I seen on the news page here a long time ago that gets rid of the wavy lines in the backround of your 1.5 PSP. You just need UMD Emulator to run this shit with flash0 Emulation set on and the system menu part on I think. Its got more info on how to use this in the readme.txt.
Its a hex edited flash0 file that u can use with UMD emulator along with your own backround images,etc so you got a backround on 1.5 without wavy lines. It works good til u turn the power off completely then u gotta reload it but that only takes like 10 secs..