Peer Stritzinger (https://stritzinger.com/) the guy behind the GRiSP project (https://www.grisp.org/) has integrated Erlang + RTEMS (https://www.rtems.org/) for the embedded GRiSP Nano HW (https://www.grisp.org/hardware#grisp-nano-details-section and https://www.grisp.org/blog/posts/2025-06-11-grisp-nano-codeb...)
His HN account with some technical comments - https://news.ycombinator.com/threads?id=peerst