Same deal with Kinetis and ST micros - there are a few BOOT pins which can really ruin your day! They are documented but it isn't super obvious. I found that

Same deal with Kinetis and ST micros - there are a few BOOT pins which can really ruin your day! They are documented but it isn't super obvious. I found that it is important to check a few parts of the datasheet/reference manual before using any part and designing a circuit: - What are the default states of every pin on start up? - What is the boot sequence? Is there a pin or setting to switch the boot between Flash, RAM, bootloader, etc? - Is there any built-in bootloader? How is it triggered? - What are the Flash config bytes/fuse settings?