Hello,
The KE18F has 64kB of FlexNVM. The FlexNVM block can be configured to be used as data flash memory, EEPROM backup flash memory, or a combination of both. You can find detailed information on how to use this and implement it in the application note AN5338.It is possible to to use the ROM bootloader as well. You can also find the information regarding the structures needed to initialize it properly as well as the commands in the following document:
MCU Bootloader Reference Manual
Please let me know if you have any further questions.
Have a great day!
Sabina
