Hi Takehiko Katsuta,
I take your case which is the same question as this post.
Now, I give some comment about my opinion.
D6 red LED is on, when the KV58 MCU flash is empty, it will also be light.
Now, please check these points:
1. Check the J21 voltage with the multimeter, whether it have 3.3V or not?
2. Connect J18, then change the on board debugger firmware with JLINK, please follow my way to change it.
1) download the JLINK driver and install it, the linker is:
SEGGER - The Embedded Experts - Downloads
2) Download the JLINK debug firmware from this link:
SEGGER - The Embedded Experts - Downloads
3) Power off the board, press the reset button, and hold on it, then plug the usb cable, you will find your board is a device named as "bootloader"

Then send the "OpenSDA_V2_1.bin" file to the BOOTLOADER, and wait the sending is finished.
4) power off the board, and power on it again, then wait the install finished.
You can find your device is the JLINK from the device Manger

5), Now use the JLINK commander to connect your board

Now follow my instructions:

Check it whether you can find the Cortex-M7 core or not?
If you can't find it, please input: unlock kinetis
Whether it can have the unlock OK?
If you still not OK, please send me your screen shoot about the JLINK commander window.
Please try it on your side.
Have a great day,
Kerry
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