So my dad just bought a 4K TV. But its a Panasonic and does not have android TV. But apparently most of the good apps for 4K content are on Android TV.
We have an android box we haven't used since we bought it really, could you flash android tv on to that, hook it up, and it would recognise the 4k tv and give us 4k content?
Just buy a real Android TV device instead of hoping there's an ATV OS build for your generic junkbox. Two devices readily available for this: $69 Mi Box or the $180+ Shield
What is make and model of your current TV box?
Likely can't do any magic to convert it to an official AndroidTV box. As a generic box you will not be able to run Netflix, Hulu or other DRM dependent apps beyond 480 resolution, if at all.
There are plenty of other 4K app options beyond these that will work but, generally you are correct.
Dude! Android TV STARTED as a "box". :-)
For copy protected, paid for 4K video streaming you need either a NVIDIA Shield or an Apple TV 4K media player.
Home networked 4K Bluray REMUX streaming really needs a device with Gigabit Ethernet both of which the above devices also have. The Xiaomi Mi Box does not even have Ethernet, it struggles with 4K REMUX's.
4K YouTube is only found on the Mi Box and the Shield, but they cannot do 4K HDR YouTube streaming.
Your best bet is to get an Nvidia Shield for 4K content, pretty much every media service is available on it. Your Android box may support 4K but unless it advertised it it's not going to.