Hello,

For a long time the Zephyr implementation of mcumgr/smp protocol over serial has not been adding length of CRC16 to the length of the packet,

although mcumgr-cli always did so. This bug has been present due to the information not being included into documentation, which has been

corrected here https://github.com/apache/mynewt-mcumgr/commit/9bd9d55d00bb70f93d85e52d7b016bbbb8c79942.

I have created Zephyr issue https://github.com/zephyrproject-rtos/zephyr/issues/39546 that describes the bug, and provided the fix here

https://github.com/zephyrproject-rtos/zephyr/pull/40127; because this fix may break something in software that is already there,

I am sending this e-mail to let you all know about that fix, so that you may voice your concerns under the issue or in the PR for the fix.

Best regards,

Dominik

Dominik ERMEL | Senior Software Engineer
Kraków, Poland
nordicsemi.com | devzone.nordicsemi.com