My friend has an old Zenith flat screen tv and I'm trying to figure out if a movie on a usb thumb drive can be adapter to plut into the hdmi port on it I've looked and looked for an HDMI to USB adapter, that is the universal USB thumb drive size, with no luck

I've looked on ebay and amazon. If anyone can assist me I'd much appreciate it. Also, is it even possible to do this ?

I assume the TV is not a smart device.

No, however you can use a Roku or Amazon Firestick and either setup some sort of DLNA server or using something like screen mirroring to project the movie from a PC or device. Does your friend have a DVD player? Can you burn a disk?

Well, I was hoping to get a usb thumb drive to work as I will be brining him tv shows or movies on a weekly basis, often several times a week. His tv is an old Zenith tv and it actually has a usb port on the back; however, for some reason, on the input options, it has hdmi and dvd player/rca type options, but there is no USB option to select to try to bring up the content once the thumb drive is connected.

So I was hoping not to have to buy dvd's frequently to burn stuff for him when I can more economically use a usb thumb drive....

Since it has a USB port, it seems wise to see if you can download the User manual for that specific model to see what is noted as it's reason for ev en being included. Often, the Settings or Setup features will have a checkbox to enable some kinds of usage. Also, if he has any manner of set top box, even if it's no longer subscribed to a cable service or whatever, those might be an access point. Getting the manual could be a big help but also undocumented usage is sometimes possible. I once had a cable service set top box with options that I didn't use back then like their own DVR function, but I discovered I could record from it's Firewire output to my PC with the addition of a PCI-Firewire card and cable.

Firewire may not be likely but the point is to discover what the various IOs can do. Thankfully I have very often been pleasantly surprised at the availability o Owners Manuals online for some really old gear. Good luck!

I sometimes use a USB-to-HDMI device to drive a "big screen" and it seems to work quite well. But, you need a "USB-C" device, and corresponding host hardware capability, in order to watch "the latest movies." If you're simply interested in watching earlier material, an "ordinary USB" device works quite well.

Note: I cannot speak to "Linux drivers" since I don't do this in a "Linux" context.

Generally USB devices work via the host controller built into the PC doing the actual communicating with what ever is plugged in like flash memory, keyboard or mouse etc. A HDMI USB adapter is just like the flash drive and still needs a host controller.

If the TV has a USB port then it should be capable of playing files from a drive. AS posted check the TV settings to see what is available or maybe the manual if it is still available.

Another suggestion similar to the Roku would be to setup a media server on a SBC like a Raspberry Pi (if you can find one) and plug that into the HDMI port. Most have a web interface and hopefully your friend has a smart phone...

My very old DLP TV has a usb and I think it could show photos. Might have needed some goofy format for video like divx.

Agreed if tv has usb port, format usb stick fat32 put files at rot and test input source