I have in hand a PSP Slim, which refuses to boot (aka Green LED light up then off). The PSP has already been pandora-ed and I already used Cory's NAND tool on it.
However, I currently do not have a NAND Dump for it. Using the Time Machine on it works and it boots to 3.40OE/1.50 kernal and so does Pandora. It installs and formats the partitions as per normal.