Changing picture styles while recording works. No Cinestyle though (from what I can tell), but it changes. Tested with original file.
Shutterspeed does nothing, sadly. Tested with Flickr Decrease off, still no change. Works in photo mode.
One way to be able to set ISO could be to have Flickr Decrease on say 1/50, have a lens with Aperture control on the lens itself, old manual, open it up and point the camera at something bright. That should set the ISO to the lowest possible value, base value. Then lock the exposure with AE lock and use Exposure compensation with a phone or computer, every stop compensated upwards should then change ISO with one stop... I'd probably just go and buy an GX80 instead :P
They seem to have this little guy locked down tight. But it should be enough for my needs, I first need to learn to actually create something nice and interesting with ANY camera.
EDIT: I was wrong about http://192.168.54.1/cam.cgi?mode=setsetting&type=recmode&value=manual_exposure. It doesn't time out with an error message, only if I push a button on the camera itself does it give "err_rejected".
Sending a value that is just a made up word gives "err_param" but any value from Grimors GH5s curmenu, like "creative_movie", "program_ae", "aperture_ae", "shutter_ae" or "manual_exposure" gives the same result; the page loading for infinity.
It's like the camera tries to do something, but locks up (not camera itself, just the command-part. Cannot send another command until I push a button and get an error on the looping one) and never finishes, until I release it by pressing a button. Never seen that kind of behavior in ANY other command. It either fails (err_param) or "OK" as an answer. Never thinking this long to try to process it.
I wonder what would happen if one would send that to a camera with a "working" movie mode, GX80 or somesuch. Does it accept the command and do some changes, or does it just freeze up as well? Gut feeling: They REALLY went to down when locking down the GX800s video mode.