Many thanks, Matas, let me know what comes back from R&D.
Any way to write a value over modbus would be helpful if ubus modbus write is not available at the moment. Python (minimalmodbus on a TRB145) works, but this is code destined for TRB246, so I don’t have python. My lua efforts gives me Couldn't connect: No such file or directory`, exactly the same as Lua-libmodbus on TRB145 - #7 by MichalPankau . ChatGPT suggested creating a Modbus Tag for each write, but I have yet to find out how.