Unfortunately many other vendors encrypts firmware updates, like Panasonic do. I dream to hack Panasonic GH5 and G80 cameras firmware to tune some options.

There is a tool to binary patching Pansonic GH4 and GH2 firmware called Ptool. https://www.personal-view.com/faqs/ptool/ptool-faq It decrypts encrypted firmware, patch binary and then encrypt again. So you can update firmware via default process.