DFU - Failed to open transport backend

[c cook]

I followed the Nordic Tutorial located here. I'm using a PCA100028 Dev Board, MCP 3.9.0.6, and a Segger J-Link Plus. I'm using Keil uVision5, and used the pack installer method as described in the tutorial, to load the dual bank dfu example.

When I start the download using the test image (zip file) provided in the dfu folder, I get an "Failed to open transport backend" error.

Why? What's causing this error?

Also - How does one debug the bootloader code? The way the tutorial describes programing the nRF51, there is no way to enter debugging mode.

-Clint

[Hung Bui]

Hi Clint,

from the log you sent, it seems that the issue came from the PC side that the access to the log file location is blocked.

672;07:55:58.7567 [480112156][ScriptMethodCallThread] Service Discovery complete
673;07:56:04.3267 [480112156][ReadPacketQueueThread] Serial port read: 04-05-04-00-00-00-08
674;07:56:04.3267 [480112156][ReadPacketQueueThread] HCI event: BTLE_EVENT_DISCONNECTION_COMPLETE ConnectionHandle: 0x0000, Reason: BTLE_CONNECTION_TIMEOUT
675;07:56:04.3367 [480112156][ReadPacketQueueThread] Received LL Connection Termination Event, reason 08
676;07:56:04.3367 [480112156][ScriptThread] Lost connection to device. Reason: BTLE_CONNECTION_TIMEOUT
677;07:56:04.3467 [480112156][] SERVER: Received packet <HciEvent: eventCode=0x0A> - <HciEvent: eventCode=0x0A>
678;07:56:04.3467 [480112156][] SERVER: Received Link Loss
679;07:56:04.5067 [480112156][MainThread] HciH4Driver closed
680;07:56:04.5067 [480112156][] Error disconnecting: The port is closed.
681;07:56:07.3667 [480112156][MainThread] nrfjprog.dll 5.2.0.45231
682;07:56:07.3667 [480112156][MainThread] JLinkARM.dll 4.92
683;07:56:07.3767 [480112156][MainThread] 609302117 - 
684;07:56:07.3767 [480112156][MainThread] 480112156 - COM11
685;07:56:07.3767 [480112156][MainThread] 681121300 - COM15
686;07:56:07.4077 [480112156][MainThread] [07:56:07.407] [EXCEPTION] ('Could not initialize log file: %s', "Access to the path 'C:\\ProgramData\\Nordic Semiconductor\\MasterEmulator\\log.txt' is denied.")

Could you check if the location is blocked from normal access ( you can try to run MCP with administrator right) ? Do you have any issue when testing the MCP with normal use (not DFU) ?

You can also try to test the bootloader via a phone (iOS or MCP )

[Nate]

Hello, I'm having the same problem, but running MCP as an administrator did not fix the issue. Nor did allowing full access to both log.txt files and the DFU subdirectories. The iOS nRF Toolbox app won't allow me to begin the update process either. I'm just using the "dfu_test_app_hrm.zip” and dfu_dual_bank_ble_s110_pca10028(nRF51 PCA10028) example from the pack installer in the DFU tutorial and it fails every time with the same error message: "FAILED TO OPEN TRANPORT BACKEND" Does DFU work with the latest versions of the SDK and softdevices? I suspect something has changed since the tutorial was written. Thanks!