Actually we have Erlang on RTEMS in production since Erlang R16B03 on a MPC8309 embedded cpu (200MHz) this is running a controler for industrial manufacturing transport system with attached RFID antennas and a distributed PLC language that compiles to beam files also.
The main work that is done at the moment is the expectedly Wifi driver stack where there was a bit unexpected extra work to do -- longer story but we needed a from scratch new USB driver which needed us to upgrade the FreeBSD network stack to the most current, currently getting Wifi connections but the FreeBSD driver we use needs some adaptions still.
The porting Erlang part is mainly rebasing to the current Erlang version and disentangling of some customer code. But we already know it generally works quite well.
The main work that is done at the moment is the expectedly Wifi driver stack where there was a bit unexpected extra work to do -- longer story but we needed a from scratch new USB driver which needed us to upgrade the FreeBSD network stack to the most current, currently getting Wifi connections but the FreeBSD driver we use needs some adaptions still.
The porting Erlang part is mainly rebasing to the current Erlang version and disentangling of some customer code. But we already know it generally works quite well.