Copy PBOOT.PBP to your base game folder, example:
	ms0:/PSP/GAME/NPUH10091/PBOOT.PBP
or for MajorGas method:
	ux0:pspemu/PSP/GAME/NPUH10091/PBOOT.PBP

Place 660.PBP in TNV_00000 save.
Transfer TNV_00000 save to Vita.
Backup and restore base game with PBOOT.PBP inside, if done correctly,
it should show up in the Live Area where your base game was previously.
Launch TN-V from bubble while hold R trigger, then install 6.60 files and exit the recovery menu.