DFU Timeout and Failed to open transport backend

[Yoshiyuki Kasai]

I'm using nRF51422 with SDK 9.0.0 and S310 ver 3.0.0. First, I program softdevice and dual bank bootloader by nRFgoStudio. After that it is possible to program my application to blank area by OTA with MCP. But DFU timeout happens around 70% programmed when I try to reprogram the same application. My application ROM size is around 35K byte.

Due to improve this issue, I changed DFU_TIMEOUT_INTERVAL from APP_TIMER_TICKS(120000, APP_TIMER_PRESCALER) to 0x800000. As the result, "Failed to open transport backend" error happens.

I checked related topics, but I can't find out solutions.

Could you please tell me how I can resolve this issue.

[Vidar Berg]

Is it the PC version of MCP your are using? I was not unable to reproduce this on my end using an application image of 62K, but have you tried the same with the ble_app_hrs dfu example for the s310 stack?

DFU_TIMEOUT_INTERVAL is reloaded when DFU is in progress, so increasing the timeout shouldn't make any difference.

[Yoshiyuki Kasai]

Yes, MCP is PC version with windows 7 and the version is 3.10.0.14. And I found this issue depended on the contents of hex files, not file size. I changed something in my project files and it happened. But I don't know what effect the error ""Failed to open transport backend". Do you know that? I'm using IAR.

I have not tried it with ble_ap_hrs dfu example, but I think it will work well because Nordic must have tested.

[Yoshiyuki Kasai]

I think I fixed it by myself. It is not perfect yet but I try to improve it by myself. Thanks, Vidar.