Hi 旺生 黄 ,
Is your MK20DX128 board new? Or you protect your board?
Please try to use the JLINK to do the mass erase at first.
In the JLINK commander, when you select the device, please select the MK20DX128xxx<ALLOW SECURITY>.
After connect, even it is failed, please input: unlock kinetis
Can you unlock it successfully, then you can connect it again, can you find the ARM core or not?
If you still can't unlock it, please check this post:
Have a great day,
Kerry
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Hi Sam,
If you are using the MKL26Z256, why you need to download the MK20 bootloader?
If you want to get the K20 bootloader, please tell me your K20 chip full name, as you know, K20 have a lot of series with different frequency.
You can check the KSDK, whether it can support your chip or not, if yes, when you generate the SDK code, in the middleware, please choose the KBOOT.
Welcome | MCUXpresso SDK Builder
Wish it helps you!
Any updated information, please kindly let me know.
Have a great day,
Kerry
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Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!
- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
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