[SOLVED] DFU: Failed to reopen transport backend

[Nate]

There have been a number of other older topics with this same error message symptom, but I've tried all the solutions proposed and none have worked to solve this specific problem for me so far. I'm simply following the official DFU Tutorial using "Option A: Packs structure" with Master Control Panel and the DFU fails. After it fails, the nRF51-DK becomes unresponsive and must be flashed via USB again before it can be connected to or discovered again.

• OS: Windows 10 MCP ver 3.10.0.14
• Project: ble_app_hrs_s110_with_dfu_pca10028 (Keil Pack)
• Update File: "dfu_test_app_hrm.zip"
• Master Control Panel Log File

Additionally, the iOS nRF Toolbox app does not enable the button to perform the update after selecting all necessary items so I haven't been able to attempt DFU over iOS.

Is anyone able to follow the same steps in the tutorial with success? I'm hoping it's simply a configuration issue with Keil and not a deeper problem. Thanks!

[Nate]

You're right! I missed that part! However, after successfully building dfu_dual_bank_ble_s110_pca10028.uvprojx, programming fails with the following errors:

nrfjprog.exe --reset --program "C:\Development\nordicExamples\dfu\bootloader\pca10028\dual_bank_ble_s110\arm5\_build\nrf51422_xxac.HEX"
ERROR: Two arguments were provided that cannot be combined. Use --help to read
ERROR: about the valid argument combinations.

I was able to program the board ONCE by removing the --reset argument, but it prevents the board from entering bootloader mode afterwards. Our final hardware won't have buttons to manually reset and boot into this mode so this could be problematic. But I still tried to resume following the tutorial after burning the bootloader. This unfortunately resulted in the exact same behavior and error message in MCP for the original post.