If PID is not found in stubs (which finsig_thumb2 current doesn't) the address should be set in a comment in makefile.inc, like on g7x
# next line is for the compatibility check, as comment
# PLATFORMID @ 0xfff20040
Note 0xfdf20040 and 0xfff20040 both likely work because ROM address space is mirrored, but the fff... version is preferred because reading it on a different camera is less likely to fail.