Hi Ateeq Ishtiaq,
You can refer to this post:
Bricking and Recovering FRDM-KL25Z Boards: Reset, SWD Clock and Low Power | MCU on Eclipse
Then use the kinetis_recovery utlity to unbrick it with your Mulitlink universal.
If this method still can't save it, maybe your chip is secured to the highest level.
You can try it at first.
About the secure, you also can read this document:
https://community.nxp.com/servlet/JiveServlet/download/857127-1-396709/Kinetis%20Lock%20issue%20anal...
Anyway, if you don't want to brick, you don't write the security in the KL43 flash configuration field.
Wish it helps you!
Have a great day,
Kerry
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