I’ve actually made the changes just now, so the latest version of the module code is in GITHUB.
You can use the new style controller to program the modules (you will need to update the controller firmware first) or alternatively follow these instructions and use AVRDUDE and an external programmer.
There is only code for the v4.21 v4.40 modules in the new controller (esp32) tree. Can I use the v421 hex file from there for the old controller with firmware from march also?