Serial number is not able to be reissued after you've lost it.
If user purchased iAUDIO as a second hand device, then user MUST takeover all the related information from a previous owner including serial numbers for the product and Jetshell. It is a user's responsibility.
If user lost a serial number of JetShell by neglect or carelessness, then you are not able to re-install JetShell.
However, you can use below serial number which is registered by CS team of Cowon. Hence you are not able to use this number for registration on our website.
iAUDIO Member 
