Intel® System Debugger - System Debug User and Reference Guide
User and Reference Guide
Some Intel processors are not factory-enabled for JTAG debugging, while others may limit JTAG-accessible functions depending on fusing, firmware configuration, board strappings, or other factors. Note that "enabled" refers to the processor core, which is required for software debugging. Even if the processor is disabled, it is still possible for the fundamental JTAG connection to work, and access to other SoC resources to be possible.