upon running activate.vpk your activation data will be backed up to pd0:/data/ and ux0:/data/ its highly recommended to make a copy on your PC as well.
pd0:data/ because its read-only and it remains even after updating or reinstalling the firmware. basicly it would be difficult to actidently delete them
(note: the writing to pd0 is the reason for the 'brick' warning in vitashell-
you cant brick from modding pd0- it holds welcome park and music files and it
only adds extra files not changing anything thats on there)