The loader software provides initial USB connectivity to the host, tools for reprogramming the USB TAP loader firmware, and the underlying software framework required to run the debugger.
When the USB TAP probe is first connected to the host USB port it runs the loader software. This is indicated by the red or green blinking heartbeat of the probe's TX/RX indicator light. To reprogram the loader image stored in the probe's flash EPROM, refer to the Reprogramming the USB TAP Firmware Image topic.