The freewificam project moved a Wi-Fi stack onto Zephyr without rewriting the Linux compatibility layer, network stack, driver, or USB host code above it. Zephyr joins FreeRTOS and ThreadX behind the same Arm real-time operating-system interface, leaving the hardware-facing software on one codebase.
The port does more than compile. On an RK3568 board with a Realtek USB Wi-Fi adapter, it enumerated the device, found 31 networks, joined an access point, answered an address-resolution request, and returned 20 of 20 pings. Board work also exposed two null-pointer bugs that another kernel had tolerated, plus a timer callback that had to move out of Zephyr's interrupt context before the USB code could wait for a transfer.
Portability claims are cheap when every target uses a stub. This one reaches the radio and moves packets, so maintainers can change the shared stack and test three kernels against the same physical behavior. The remaining measurement is throughput, which the project explicitly leaves open rather than inferring from a successful ping.