I am trying to boot from a USB stick, but it shows the error you can see in the screenshot. I am using the update button on the back of the TV box. It does start the boot process from the USB, but according to the error message it seems unable to actually read the drive. I have been stuck on this issue for several days now.

The s905x3 one. Also, how are you booting this? You say it doesn't recognize usb, so what are you using to boot Armbian?

Thank you very much for your responses, it totally make sense. I will try to build it myself, tho I have never done that, and my knowledge is very limited. I'd love to help one day, but this really is beyond what I can offer, for now.

Thanks for clarifying. And which would be the correct version of u‑boot for my BTV OTT BOX (model B11, Amlogic S905X3)? I admit I’m a bit lost at this point.

The screen shot you have shows you are using the Ugoos X3 version of uboot. That will not work as that is specific to that box.