RE: DFU over UART: Response code Invalid Object (NRF528240)

Edvin — Tue, 18 Dec 2018 11:38:27 GMT

Hello,

From your numbered points, I don't see what the problem is. Is there any problem here?

Regarding debugging:

The issue here is that when you do a DFU using a bootloader, the bootloader will verify that the application is valid, and store this this information based on the application image in a bootloader settings page.

The issue when you are debugging is that the IDE will upload a copy of the image. In theory this should work fine if you don't change anything in the application that you just uploaded with DFU, but it turns out it is a problem after all. The issue is that the different compilers uses different padding for variables shorter than 32 bits. Some uses 0's and some uses 1's. This changes the CRC of the application, and if the application is updated, it may corrupt the CRC check stored in the bootloader settings.

If you want to debug your application while you use bootloaders, you should use the debug project folders for the bootloader: pca10056_uart_debug. This doesn't check the CRC of the application, and debugging, which will update the application and corrupt the CRC will still work.

Best regards,

Edvin