How to format bootloader space of nRF51-DK?

[Nilesh Bhavsar]

Hii,

I am trying to update new firmware in nRF51-DK.

But unfortunately, wrong image file is uploaded.

Now i am trying to once again same process then getting no space available error.

[Hung Bui]

Please let me know what did you do to get to this error ? Which guide you are following ?

The image you attached shows that you are downloading firmware for the Segger chip, not the nRF51 chip. If you planning to download segger chip firmware, you should use the firmware nRF5x-OB-JLink-IF that you can find here.