Hi Sebastian Lenz,
I already tried the bubble code in the KSDK2.0-FRDM-K22F120M, and I can use the Kinetis bootloader 2.0 to download it, now, please follow my step:
1. Download the flashbootloader to FRDM-K22F120M board
open bootloader code in folder:NXP_Kinetis_Bootloader_2_0_0\NXP_Kinetis_Bootloader_2_0_0\targets\MK22F51212
Then build freedom_bootloader, flashloader and flashloader_loader

After you build it, then download the flashload_loader code to your FRDM-K22 board, then press the reset button on the board.
2. Generate the bubble.bin code in the KSDK2.0: SDK_2.0_FRDM-K22F\boards\frdmk22f\demo_apps\bubble\iar
You don't need to modify the link file, just generate the bin is ok, I already attached the bubble.bin
3. open KinetisFlash Tool in the Kinetis bootloader 2.0: NXP_Kinetis_Bootloader_2_0_0\bin\Tools\KinetisFlashTool\win

configure it like the above picture, but the com port you should select your board's com port on your PC.
After configure the Com port and baudrate, then click the connect button, it will have the connected to device successfully.
Then select the image file, just add the bubble.bin, then click the update button, the code will be download to the board, after download is ok, the bubble code will run.
I already check it on my side, it works ok on my side.
Besides the kinetisFlashTool, you also can use the blhost: NXP_Kinetis_Bootloader_2_0_0\bin\Tools\blhost\win
This is my test information:

Take care, each time after you download the app, you need to download the flashbootloader code at first, which you can find in step1.
Wish it helps you!
If you still have question, please contact me!
Have a great day,
Jingjing
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