Hi.
I am using a 1tb HDD on both a h2s & h5.2s. Both record fine with no problems, so maybe best to get a drive. It may be that the read/write speed of the usb stick is a problem, maybe.
Is it a usb3 stick? I have read somewhere that usb2 is best to use. My drives are usb3, & no problems.
Can get 1tb drives, from £36, on ebay. Would put a link here, but not sure if I'm allowed?
Just to add: It might be worth trying, restart your network. I was getting a lot of glitching & restarted the network on my h5.2s. Don't know why, but it solved the problem. I didn't reboot the router, though that might be worth a try too, just on the box. I'm using 500mbps homeplugs.