I found that KBOOT for K64F default clock system is 120MHz PEE mode and clock source input 50MHz.
But for bootloader typically use, default FEI and use internal reference clock source would be better idea.
I need UART and HID bootloader function, so I have to use FEI and use internal 48MHz for USB.
Original example code for K64F bootloader include a "system_MK64F12.c", but it is an old version.
I found a newer version is at "FSL_Kinetis_Bootloader_1_1_0\src\startup\MK64F12" and modify to use "CLOCK_SETUP 0".
UART for bootloader is functional but HID is not work.
Is there any idea regarding how to modify to make HID functional?