Hello Robert,
Please select the OpenSDA firmware for Segger Jlink at here :
OpenSDA Serial and Debug Adapter|NXP

After you choose "Segger Jlink V1" , you will run into Seeger website ,
SEGGER - The Embedded Experts - Downloads - J-Link / J-Trace
then you can download the firmware, please use it update your bootloader.

Hope it helps
Have a great day,
Alice Yang
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