DFU: Failed to open transport backend

RE: DFU: Failed to open transport backend

Hung Bui — Thu, 13 Aug 2015 07:08:10 GMT

Hi George Philip Orais,

The error code you reported is pretty similar to this case's, could you check if it's the same issue and solution ?

RE: DFU: Failed to open transport backend

George Phillip Orais — Fri, 20 Mar 2015 03:18:26 GMT

I just remember, what i noticed is after successfully downloaded the gcc-compiled-app to the chip through OTA, i still can switch to DFU via DFU service. Then i can see the new advertised device name, which confirms its on bootloader now. But once i connect and discover the services, it will have a long wait on the last handle? I think it was handle 0x000F? It seems the MCP was not able to receive the expected reply from the device, any ideas? Did the gcc-compiled-app corrupted the bootloader? But the size of the app is not that big..

RE: DFU: Failed to open transport backend

George Phillip Orais — Fri, 20 Mar 2015 03:18:23 GMT

RE: DFU: Failed to open transport backend

George Phillip Orais — Fri, 20 Mar 2015 03:08:07 GMT

Hi Matt, I see, that's what i expected. Yes i agree, i think just need to fully understand about the DFU bootloader. I will try SDK 8 later and update you what i will get, thanks again for your reply.

RE: DFU: Failed to open transport backend

George Phillip Orais — Fri, 20 Mar 2015 02:56:02 GMT

Hi Stian, thanks for your reply. I see, i tried the ble_app_hrs but still the same result: the keil compiled works fine but the gcc compiled cannot proceed with OTA once the app is downloaded at first attempt through OTA. Actually im using MCP3.8 and SDK6.1.0 but it works fine if both bootloader and apps are compiled with Keil.

Yes, actually im using the Nordic dev kit for now just to see if GCC app with DFU works.

I also already tried that boot loader but still it can't, it has a different error though.

OK that's what i'm planning for later test, i already downloaded SDK8, will update you for the progress, thanks again for the help.

RE: DFU: Failed to open transport backend

Matt Barr — Thu, 19 Mar 2015 17:25:52 GMT

Hi George, I don't believe there is a free version of IAR and the licensed version is also expensive. Based on Stian's results, it sounds like there should be no bootloader vs. application tool chain dependency. I needed to make changes to the bootloader, this was the primary reason for migrating to IAR. I was using the 7.2.0 SDK and bootloader, and the 7.1.0 Softdevice. I'm not sure how that might change tool chain dependence if at all.

RE: DFU: Failed to open transport backend

Stian Røed Hafskjold — Thu, 19 Mar 2015 12:25:29 GMT

I tried with a Keil compiled bootloader from SDK 6.1.0 and SoftDevice 7.1.0. I was able to upload the ble_app_hrs example application in SDK 6.1.0 both compiled with Keil and GCC. So it should be possible. However, I was using MCP 3.7.1, since the 3.8 version requires an init file, and as far as I know that is not compatible with the bootloader from SDK 6.1.0.

You are sure the application compiled with GCC runs on the board without using the bootloader right?

You can also check out this bootloader example: github.com/.../nrf51-dfu-bootloader-for-gcc-compiler. This is a bootloader based on SDK 6.0.0 that can be compiled using gcc.

Maybe you should consider migrating to SDK 8, since the bootloader has been changed significantly since SDK 6?

RE: DFU: Failed to open transport backend

George Phillip Orais — Thu, 19 Mar 2015 02:47:21 GMT

Hi Matt, Thanks for your reply! I see, yes i also agree to build both with same tool chain which i confirmed via Keil. Because my application is already 33KB in size i need to use GCC for i cannot afford full version of Keil. How about your IAR, what is the size limit for the free version? Maybe its bigger than Keil?

RE: DFU: Failed to open transport backend

Matt Barr — Wed, 18 Mar 2015 15:01:43 GMT

Hi George, I've had similar bad luck with a Keil compiled bootloader and IAR compiled application. I do not recall what sort of error message was reported by the Android MCP I was using, and I never did debug this. I wound up porting the bootloader to IAR, I find that DFU works when application and bootloader are both built with the same tool chain, Keil or IAR.