I used AN4368 a while ago to customize the USB MSD Host bootloader for the MCF52259 MCU, and it works OK. Now we are upgrading to the Kinetis MCU and I'm wondering if I should try to adapt the same bootloader code to that MCU (K22FN1M0), or try to use the new KBOOT. Neither of these support have this MCU directly, so I assume I would have some work either way porting from K60 or K64 to the K22, but I'm not sure what would be easiest/best/recommended. The KBOOT documentation doesn't seem to go into much detail on customizing (neither did AN4368 but I already figured it out somewhat), and the projects are for IAR where I prefer using CW. I was inclined to go with AN4368, but I saw the KBOOT released recently and being suggested by a few people on the forum.
I'm wondering if anyone has any experience creating or customizing a USB MSD Host (not USB device) bootloader for the K20-series, by either of these or any other method?