It is based on Debian (Droidian to be specific I believe), which to me reads as a fork or maybe a distro flavor with out of the box tweaks to specifically work with the hardware they are selling.

They say they aren’t stopping you from installing anything else you want on the phone, they just aren’t going to offer help getting a different OS to work, which is reasonable to me.

https://furilabs.com/shop/flx1/

I’m already seriously considering giving this a go as my next phone soon. My current phone is desperately in need of replacement.

If it goes well I will be vocal about it.

Maybe shit like this will push them down that road faster. We need options for sure.

Roads. It is pretty common around where I grew up to notice you are in a different states when there is a sudden shift in road conditions. They never communicated about when to do repairs or anything, so it was almost always an obvious line between either a really shit road and a smooth one, or vice versa. Sometimes you could even tell based on the noise or feel of the road, if the other state uses different road construction materials.