hmm only thing I know about my TV in regards to the USB port is that the flash drive has to be formatted as Fat32 as for it wont find NTFS. Same goes for my blu-ray player and its 2 USB ports at front and back. I am limited to 32GB of data on a Fat32 partition with no other partition types supported. Also my TV doesnt support playback of any videos, the USB port only can be used to show pictures which is sort of a waste since how many people will plug a thumb drive into their TV and go , hey look at the vacation pictures. The fact that my TV didnt come with video player support for digital videos on its USB port was kind of stupid, but the Sony Blu-Ray player makes up for the feature limitations of the TV.
Also I also own a Chromecast, but havent used it much actually. I plugged it into the HDMI and used this otherwise worthless USB port on the TV to plug the USB portion of the Chromecast into the TV, so that the USB port that is otherwise worthless is able to power the chromecast for the chromecast to play videos through HDMI connection.
My complaint with Chromecast is that:
#1, you need a computer with Chrome browser running side by side the TV to play videos, its not a stand alone player. ( If I already have a laptop with HDMI port on it, and its required to run side by side the TV to play videos.... I might as well just plug HDMI cable directly between laptop and TV and not bother with Chromecast and forced to use Chrome browser which I dont care for with Firefox as my preference. )
#2, you are limited to what it can actually play. Not all web sites that have videos are supported. ( You cant use it to send a clone copy of your display to the TV when playing games with a wireless keyboard and mouse .... so I might as well connect a HDMI cable directly vs use Chromecast )
Pretty much Chromecast is a cheap way for people to make their TV into a Smart TV, BUT if you already have a laptop with HDMI port, its kind of pointless because you can quickly turn your laptop into a HTPC with HDMI cable between PC and TV to play the movie or video game on the larger TV screen.
I have been tempted to sell my used less than 4 hours Chromecast, but after all it was only $30 and cant be worth much used anyways.