On: ESPHome

[cyberax]

RS-485 is a shared bus, so you need to use some kind of a protocol to arbitrate access, and to make sure you don't flash unintended devices.

BACnet is one example, but other protocols can work too.

[epcoa → cyberax]

https://esphome.io/components/modbus_controller.html

[cyberax → epcoa]

It doesn't allow firmware updates over modbus. The same would also apply to Zigbee.