You can install OpenATV from openpli by putting the image in the root of the USB as ZIP file as you download it from their website... so not unpacked... You can find it via the downloaded_images expension.
downloaded_images?
I'm afraid I cannot see that.
I downloaded the following file: openatv-6.2-mutant51-20180907_usb and put it in the root of my Kingston USB and it is not in the Flash Image utility.
You must replace mutant51 with hd51 in image title.