C3000 can't get USB fileshare to work

I have a C3000 modem/router. Trying to get the ReadyShare to work with the USB port. I plugged in a flash drive, it shows up in the genie console as enabled. Workgroup matches my Win10 laptop. But can't access it with \\readyshare UNC. Can't get to it with network access either. Called NetGear support and they told me only 4 flash drive models are supported, period. Of course from the doc these are the only four they tested. Doc says it should work with most USB flash drives and hard drives. I tried with two external USB hard drives I have, but still can't access them.