If you doubt your RasPiKey is faulty, insert it into your Raspberry Pi and see if it boots. If it does, that means your RasPiKey is functional and not faulty.
Why can we be so sure?
We provisioned every RasPiKey by plugging it into a USB SD card reader and use "dd" command to fresh the disk image into it. When a RasPiKey has been provisioned successfully, it means:
• It is recognized as an SD card (via USB SD reader) on PC
• We can write data into RasPiKey like a normal SD card
• We can read data from RasPiKey like a normal SD card because the dd command will verify the written data.
When you insert your RasPiKey into your Raspberry Pi and successfully boot the system, it means:
• It is recognized as SD card, because Raspberry Pi is not expecting something else in its SD card slot.
• The Pi can read data from RasPiKey, otherwise the system can not boot.
• The Pi also writes data into RasPiKey, system log files are written during the boot.
So a successful boot should ensure that your RasPiKey is not faulty.
Why is your RasPiKey not recognised in PC then?
There may be different reasons, but the most common reason is unreliable connection. Please try to pull out your RasPiKey and plug in again, maybe with slightly different angle, there is chance that a better connection is established and your RasPiKey gets recognised.
Sometimes the issue is due to the SD card reader itself: although it is not very common, some SD card reader doesn't support RasPiKey, even the connection is good. Please try a different SD card reader in such case.
Sometimes the issue comes from the SD->Micro SD adapter (if you are using it). We found that if such adapter is used, it has rather big chance to cause problem. You may change adapter or use an SD card reader with micro SD slot.