Modbus protocol is widely used in industry networks and Modbus devices often need firmware updates due to firmware fixes or improvements. There are many projects that implement this feature with various approaches, but I think that my solution for the task is very efficient and I’ve never seen it in other projects before. Modbus network can contain up to 247 devices and it’s not a simple task to update firmware for such a large number of devices with a relatively slow bus. But you can use so-called “broadcast” messages (messages with address 0) to let your firmware update packets be received by all the devices in the network. Such a solution makes it possible to update all the devices of a similar type in the network at the same time for about the same time as if you were updating a single device. I have implemented such approach in one of my projects a long time ago, but recently I developed even a better, elegant and fast Modbus bootloader. This firmware is planned to be prepared for commercial use.