A device holder assembly for use in a vehicle includes a compartment having a top side opening, a device holder attached to the compartment for holding a mobile electronics device, and a closure attached to the compartment. Each data storage device may be configured with a user invisible diagnostic region where diagnostic information is stored in logical block addresses beyond a storage capacity of the respective data storage devices and the diagnostic information can be accessible via read and write requests to LBA beyond the storage capacity of the respective data storage devices. In this manner, the transmission rate for the port can be effectively limited to accommodate, for example, a lower transmission rate for a port on a destination node.