A day of misery with various micro-controllers. More to be explained over the coming days, tales of misery and imagination involving LPCExpresso and Kinetis Studio….
But for not the misery was a Kinetis K64F that seemed to not boot reliably. The answer is need pull up R75 or remove a capacitor. It all relates to NMI. Until I write up a better post see here
Short version answer to this is answer here

10K resistor populated in R75 by the tricolour LED or handle NMIs….

The  NMI handler. On a K64F the  interrupt vector resides in bytes 8-9-10-11, also NMI connected to SW3.

And some notes on how to write your own boot loader!