Yes the HDMI port is fuctional, you need a Micro HDMI to HDMI lead.
If you keep it short ( less than 3mtrs ) it works, over that length and you need a ‘repeater-booster’ inline but its a bit trial and error as it takes power from the teclast hdmi port.
Excellent quality image on a full HD TV,, would thing its astounding on a UHDTV
Mine has one major problem which I am trying to fix…. as soon as the tablet see’s the device ( TV etc ) on the HDMI it flips the image upside-down on the Tablet and shows the image on the TV correct way round. Both rotate due to the G-sensor action so both images are inverted to each other no matter which way you turn the tablet.
( You cannot access the ‘screen lock’ function to disable the G-sensor on the Tablet when it is connected to a HDMI device )
If you have a smart TV with ‘screen mirroring’ that also works wirelessly ( on mine its also inverted ) but the TV image lag behind the Tablet is unbearable to use !