Can't select device in DFU mode using nRF Toolbox

[jm]

Hi all,

I have a question to complete the tutorial 'Setting up device firmware update(DFU) on the nRF5 DK'.this

I have tried to set up my nRF51 Development Kit. Everything was Ok, but when I look for my device in DFU mode using nRF Toolbox, I can't find my kit.

All devices are always 'n/a'. Should I change my device's name in uVision to detect it? Or is there anything else I need to do?

Please give me some advice.

Thank you in advance.

[jm]

Thank you! Your comment helps me understand what the problem was.

1.I flashed that hex file using nRFGoStudio and tried to select, but I couldn't find my device.

2.So I tried to download Keil project "..\examples\dfu\bootloader\pca10028\dual_bank_ble_s130\arm5_no_packs\dfu_dual_bank_ble_s110_pca10028" , but the following error has occurred.

Reading flash area to program to guarantee it is erased. ERROR: The area to write is not erased.

How can I fix it?