I saw a comment about needing to unplug the USB stick when upgrading FW versions....is that correct? Just for a dirty upgrade from B2 to B3?
No need to physically unplug, just unmount it from the gui and update the FW. As a best practise, you should just unmount any usb device attached to avoid any issues - usually device reboots, but does not run the FE update when usb storage attached