Today M33 have decrypted v3.71 Firmware, and below are the details from their PSAR Dumper update:
Download: [Register or Login to view links] [Archive Pass: PSARDUMPER_FOR_NEW_AGE]
This is a recode of psardumper for 2.XX & 3.XX kernels.
If you are in a cfw of the fat psp, be sure to put it in GAME3XX or in GAME if you have it configured for 3.XX kernel.
Support for 3.7X decryption has also been added.
The instructions are same as for original psardumper, except that you don't need the DATA.PSAR in the root of memory stick, but instead the EBOOT.PBP; this is to make it more noobs-friendly and lazy-friendly.