I did this too now ;)
With some more changes and what I think could be improvements...: https://github.com/nica-f/k5prog
With my version yo can now transparently flash raw binary firmware and also the "encrypted" either manufacturer version or what is most usually also created by the modified firmware projects (most often called "packed").
Since flashing for me is super reliable I remove the "-YYY" for flashing and modified the output to stdout a bit to be a bit more user friendly and less scary :)

Problem is though that for better undertstanding/reading of the code I also massively changed indentation and pretty printing :( That makes a merge a bit difficult... need to think about this... maybe I'll create another branch and just add the real changes and leave the pretty printing and indentation alone.

Anyway... wanted to mention it here...

And most importantly: A massive THANK YOU to sq5bpf and all the others contributing to the UV-K5 projects! I had and still have a lot of joy and fun with these small radios and all the free software around them!