It should be a thing because most (all?) "smart TVs" run some variety of Linux, which, as Free Software, is supposed to guarantee the device owner's right to modify the software running on the thing. However, in most (all?) cases, the practical ability to do that has been destroyed by subverting encryption functions against the owner in a process called Tivoization.

In other words:

1. No, it isn't really a thing,
2. It's wrong for it not to be a thing, and
3. You should be pissed off about it.

It's similar to console hacking. If there is no known exploit, the device is not yours. LG patched the exploit that made that possible for my smart TV and know I need to wait for another to be doscovered. Unfortunately the Smart TV hacking community is not that active.

https://github.com/RootMyTV/RootMyTV.github.io

https://xdaforums.com/t/getmein-one-time-rooting-jailbreaking-tool-for-webos-lg-tvs.3887904/

In principle, yes, and I believe a few small hobby projects have attempted to do this and support specific TVs. However, interest in developing a custom Smart TV platform tends to get siphoned away into a project where the output from your actual platform is displayed on the TV rather than running directly on it. Simply, it’s easier to develop and maintain support across different models.

Why would you develop a custom TV OS that runs on one TV when you could develop it for any mini PC and immediately support all TVs? You’d have to develop your OS to run on each specific TV model which will make it quite hard to reach a critical mass sufficient to attract attention from developers and users alike.

The juice isn’t really worth the squeeze. It’s not like TV vendors are publishing detailed hardware specs and drivers. Writing or even porting an OS is hard. Look at the state of the Android ROM scene, and that’s about as good as it gets when some vendors are actually attempting to open source their drivers. The difficulty is much higher and the interest lower due to the existence of a viable alternative.

With that said, motivated minds have done it anyway. You just need to have the right TV for it.

It is still possible to buy "dumb" TV's. Tons of businesses need them for display purposes (like at fast food restaurants and corporate expos, etc, etc), but you need to search for commercial displays. Like this one.

Usually that means trying to get Android TV working through USB, but it depends on what tv you have. If you already have an Android TV, just use a launcher like Projectivy. Most people just buy a media box: either an Android based one or apple tv and disable the "smart" tv altogether

Get a dumb TV and plug in a cheap computer where you can pirate everything

Nvidia shields with an alternate home screen have been a good solution for me? TV isn't connected to the network directly, just to the shield.

I've got RetroArch, Plex, Spotify on each of them - that sort of stuff.

It's much easier to run a HTPC on something small like a Raspberry Pi, or an NVIDIA Shield. The hardware on your TV is probably the bare minimum to run its own smart features, and replacing the firmware doesn't guarantee that the TV isn't still phoning home with your data.

Also cars. I want a custom, privacy respecting OS for an EV please

Technically yes, you'd have to find an exploit for your TV that allows for installing your own OS.

It's not super feasible but it's technically possible.

This is a damn good question that I would also love an answer to!

Best is to try to get the dumbest TV you can and plug in an android tv streaming box to it imo

I have another question.

Can we reprogramme the remote buttons that open Netflix, YouTube etc., so that they open other apps like Jellyfin or something?

What I did was bought a "commercial" television that's intended to either be put in a waiting room and tuned to Fox News all day, OR used as digital signage. It's not quite an Arby's menu board because it's still obviously a television, has a tuner and such, but it has no "smart" TV in it and the backlight isn't as "won't survive a run of Breath of the Wild" like the TCL televisions my parents own. Then I slapped a Raspberry Pi 4 on the back with OSMC on it. Meanwhile I did replace my small form factor desktop gaming rig, so I have a Ryzen 3600/GTX1080 rig sitting unplugged under that television waiting for me to build up the gumption to switch over to it.

Yes. What brand or model number do you have?

I bet somebody's done it. There are people in the Linux world who dedicate themselves to getting it to run on anything - a TV, a toaster...

But it would probably be a lot easier to just run Linux on a Raspberry Pi or something and use the TV as a monitor.

I'd think most people woud go for a cheap used ultra Small Form Factor pc or raspberry pi set up as an htpc. Plug in to either tv screen (via hdmi ) or monitor / projector directly. Never connect the tv to the internet - or even to your LAN if you're really paranoid. You can arse around with a remote control a bit bodgy, or just use wireless Keyboard/mouse.

I cant imagine spending the time to jailbreak a tv to get less functionality for more hassle - but i'm sure some crazy will have done it - good luck finding them though.

It is possible but it needs people to develop the OS for each brand of TV and jailbreak the TVs to run another OS.

Most TVs are like phones in that they have a locked down system and their bootloader/BIOS/UEFI is also locked down which is what ultimately needs to be unlocked to allow another OS to be installed.

Why there isn’t?

Just not really many developers interested in creating an OS for it. Probably because of so many different brands and models of TVs that would require lots of work since each one is pretty different from another.