Even though there probably is not much to add to this topic, because @Sunny did an excellent job providing great information, I would like to leave a link to my video review and article that contain few more details and more visual info.
Entire Firefly 6S review can be found here
And here is a video review
Hopefully Sunny does not mind me posting this here.
Excellent review. I believe the colour is probably quite bad because they're not taking advantage of the 3D LUT colour processing capabilities of the novatek chip. Im guessing they dont really have the knowhow to program their device properly.
Its really disappointing to hear about the customer support but thats almost expected. These companies are just manufacturers/factories. They dont care about the customer. Thats for distributors to deal with.
In the end I only ordered one because of the price, if I'm unhappy, I will probably buy a gopro. The xiaomi yi has good image quality but cant change settings when you're in the water. I got the firefly 6s for a tropical island holiday after all!