Hello Customer,
If you want to use the kinetis flash tool to download the application code to the bootloader, you need to use the debugger to download the freddeom_bootloader to your chip at first.
I don't know what the IDE you are using, now take KBOOT2.0 IAR project as an example.
You can download the KBOOT2.0 from this link:
NXP_Kinetis_Bootloader_2.0.0 package
1. Download the freedom bootloader, you can find it in folder:
NXP_Kinetis_Bootloader_2_0_0\targets\MK22F51212
Choose the project freedom_bootloader, build an download it to your chip.

If you are using KDS project.
Add this below code in bootloader_config.h
#define BL_TARGET_FLASH 1
2. Application code prepare.
From the freedom_bootloader file bootloader_config.h.
#if !defined(BL_APP_VECTOR_TABLE_ADDRESS)
#define BL_APP_VECTOR_TABLE_ADDRESS 0xa000
#endif
So, you need to relocate the application code to address 0xa000.
You can use led_demo_freedom_a000.bin in folder:NXP_Kinetis_Bootloader_2_0_0\apps\led_demo\MK22F51212\iar\binaries
3. open KinetisFlash Tool
Configure it like the following picture.
Before you click the connect button in the kinetisFlash tool, please press the on board reset button at first.

After connect successfully, press the updated button.
You will find it download successfully.

Then the on board LED will binking.
Please try it on your side.
If you still have question, please let me know!
Have a great day,
Kerry
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