Hey there tvlangs24,
I apologize for the late response, thank you for being patient! Were you able to fix that flash drive issue? If not, I'd be happy to help you out, since this issue sounds pretty frustrating. First, I would double-check to see if there are any more updates for your Chromecast. Then, I would unplug the USB Hub and connect it to another device, to make sure it's still working. Then, I would restart the Chromecast, and plug the USB Hub back in and see if the Chromecast can detect it.
I look forward to your response, and if you have any other questions or concerns for me, please let me know!