The Kria™ KD240 Drives Starter Kit has a primary and secondary boot device that provides isolation of platform-specific boot firmware from the runtime operating system and application. This allows you to focus on developing and updating your application code within the application image without having to rebuild and flash boot firmware. The primary boot device is a QSPI memory located on the SOM and the secondary boot device is an SD card interface on the carrier card. By default, the KD240 Starter Kit carrier card sets the XCK24 boot mode to QSPI32. The SOM boots up to U-Boot using the QSPI contents and then U-Boot does a hand-off to the secondary boot device.
The overall boot device definition and firmware contents are outlined in the following figure.