Cannot connect Netgear NAS RN214 during USB Recovery

That's because you have to TELNET into it in that condition, not use a browser.  But it tends to indicate that the USB recovery didn't work completely.  Since it seems to have done something, maybe just try again with the same USB.  If that doesn't work, try re-creating it and try recovery again  I recently had a NAS take 5 tries with the same USB I've used on others before it worked right.  Figuring something had happened to the USB content, I re-created it after the second try, and it still took 3 more (without re-creating yet again) to work right.