Remount Ejected USB without Replugging - OS X
You can use this command line to unload and reload the USB kernel extension.
sudo kextunload /System/Library/Extensions/IOUSBMassStorageClass.kext
sudo kextload /System/Library/Extensions/IOUSBMassStorageClass.kext
Instead of ejecting, you can also use diskutil to unmount and remount later.
sudo kextunload /System/Library/Extensions/IOUSBMassStorageClass.kext
sudo kextload /System/Library/Extensions/IOUSBMassStorageClass.kext
Instead of ejecting, you can also use diskutil to unmount and remount later.