| Operating system | Developer | First release | License |
|---|---|---|---|
| FreeRTOS | — | 2003 | MIT License |
| Nut/OS | Ethernut | 2000 | BSD licenses |
| OpenTX | Bertrand Songis | — | GNU General Public License |
| OpenWrt | Gábor Juhos, Florian Fainelli, Hauke Mehrtens, Jo-Philipp Wich | 2004 | GNU General Public License, version 2.0 |