DFU bootloader - CRC always 0, always accepted

RE: DFU bootloader - CRC always 0, always accepted

tellg — Thu, 23 Jun 2016 12:52:54 GMT

Thanks to both. I will use Erik's solution until then.

RE: DFU bootloader - CRC always 0, always accepted

Vidar Berg — Thu, 23 Jun 2016 12:43:55 GMT

Thanks for the input. I completely agree with you, and have already reported this as a feature request internally.

RE: DFU bootloader - CRC always 0, always accepted

Erik — Thu, 23 Jun 2016 12:38:47 GMT

Maybe a #define could enable/disable it, or at least it could be commented in the code that m_image_crc is not in use. Now it looks like it is implemented, but actually its not in use. Gives kind of a false security. Also an application modifying its own image is not very safe and I don't see why that sould be the default.

RE: DFU bootloader - CRC always 0, always accepted

Vidar Berg — Thu, 23 Jun 2016 11:35:58 GMT

this is a deliberate choice made by the developers as some may want to change their application at runtime, but can be added for those that want additional safety.

RE: DFU bootloader - CRC always 0, always accepted

tellg — Thu, 23 Jun 2016 11:32:46 GMT

Hello Will the next SDK have this re-implemented? Should this be added to devzone.nordicsemi.com/.../

RE: DFU bootloader - CRC always 0, always accepted

WestCoastDaz — Tue, 24 May 2016 15:46:47 GMT

Erik,

Thanks for adding your solution!

Cheers, Darren

RE: DFU bootloader - CRC always 0, always accepted

Vidar Berg — Mon, 23 May 2016 11:58:27 GMT

Hi,

The CRC check of the application image on boot is disabled in the newer SDK examples ( .bank_0_crc is just set to '0' ). This is done in case the application needs to modify its own image in flash at runtime where having a CRC check would have caused any following startups to fail.

But the application image will normally not be modified as user data is typically stored outside of the application image in the 'app data section'. So unless the appliation is writing to its own flash area I think makes sense to add CRC check on startup as an extra safety measure. @Erik's solution for adding it is correct.

RE: DFU bootloader - CRC always 0, always accepted

Erik — Mon, 23 May 2016 07:51:35 GMT

Hi Darren, I updated the question with my solution. Cheers, Erik

RE: DFU bootloader - CRC always 0, always accepted

WestCoastDaz — Fri, 20 May 2016 23:27:25 GMT

Erik,

I noticed the exact same problem and was planning on posting a question about it. Are you able to share your solution for review?

Cheers, Darren