KL25Z unabled to debug. Programmed flash is protected and can't be read out.

[Raul_CN]

I'm using the KL25Z board for the first time so when I tried to debugg my code using the J-link Segger I get the following mesage:

Protection bytes in flash at addr. 0x400 - 0x40F indicate that readout protection is set.
For debugger connection the device needs to be unsecured.
Note: Unsecuring will trigger a mass erase of the internal flash. If 'Do not show this message again' is selected, mass erase will be performed automatically in the future."

When I clicked "Yes" produces the further message: Failed to resume target process. Not allowed to access registers while running.

How can I solve this problem??

[Sabina_Bruce]

Hello ,

Hope you are doing well.

Could you please attempt to connect it to MCUXpresso and use the flash tool to do a mass erase. 

Please let me know if you are able to connect it or not to MCUXpresso IDE to do the mass erase. 

You may also refer to the following document for more details:

Bricking and Recovering FRDM-KL25Z Boards: Reset, SWD Clock and Low Power

Best Regards,

Sabina

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