All Panasonic photo cameras use proprietary LSI chips.
CPU command set looks like NM103.
If you want to research or modify GH1, TZ5, TZ7 etc firmware here are necessary tools
My firmware manipulation tool
It allow you to strip all unnecessary info and disassembly firmware, after modification you can use same tool to make all necessary checksums.
Unfortunately this version can't recalculate big 32 byte digest at the end of firmware.
According to my information it uses double MD5.
MN103 module compiled for IDA 4.9 Free
So, you don't need to pay anything and can legally disassembly Panasonic firmware files.
Original module source author is Hitman, plus few other guys who worked on jump tables.