UPDATE 1
The firmware have been merged based upon original CW for K60 to IAR for KL25Z. Also I reuse code from AN2295 for its flash driver and simple drivers for timer, watchdog and etc.
The source code is built successfully. I attach my very first version here. However, it is not a working bootloader. I have not made it working on FRDM yet.
I put it here just in case someone who need it urgently and want to debug by himself. And don't freak out if you find the source is too messy.
I will release my final code with FSL community. It will be a very simple version without verification, authentication, personalization and other features.
However I have to say. FSL should help us to develop and verify all the bootloaders, including AN2295 serial bootloader, AN4370 USB DFU bootloader, AN4379 USB MSC bootloader, as well as other bootloader including USB host MSC bootloader, SD Card bootloader, Ethernet bootloader, CAN bootloader, I2C/SPI bootloader.
At least, FSL should align a standard driver for bootloaders, including drivers for K/KL flash memories, USB interface, serial com, file parser, FAT File system.
Yours sincerely
Allan K Liu