Sometimes it is useful to share code across multiple kernels -- we avoid doing the work twice. However, this might be complicated when one version is using Zephyr with a Cortex-M, and another Linux on a Cortex-A. We will explore this problem using an example of the door lock blueprint from the Eclipse Oniro project - an implementation of basic door lock functionality. For a typical use-case, a Cortex-M with Zephyr is more than sufficient, but we might also want to integrate the same application in a bigger one using Linux on a Cortex-A. Will we find a way to do so?