Its just been posted in the forums about a new exploit uncovered by Yoshihiro and the wab team, heres some of it:
How To :
!!! HOW use it !!!
Put your two folders on your games folders and run it .your game boot
and freeze your psps on white screen .after your psps shutdown it's
because your second eboot.pbp like on kxploit "From pspsdev team for psp 1.5"
is corrupted juste find teh 02000800 and replace the 08 by 01 for test in
the header of your elf it's easy but it's proof concept the psp 2.0 can read
the elf but in another format .