The secondary boot device on the KD240 Starter Kit is the SD card. It contains the operating system image and associated application files. The KD240 Starter Kit accelerated application references are built on the Linux operating system. The Getting Started web page provides a pre-built reference image that can be written to a microSD card for out-of-the-box functionality. SOM board support packages (BSPs) are also available if you want to customize your OS.
Recommended: The SOM is designed to use SDHC standard microSD cards. See AR66779 for a list of tested microSD cards.