DFU stands for Device Firmware Upgrade and you’ll be sure to see this term again and again in the jailbreaking community. DFU mode is a state that allows you to put your iPhone to interface with iTunes, but does not load iOS operating system or boot loader. That’s the main difference between DFU mode and recovery mode.
As part of our experience in supporting hardware manufacturing companies with our software development, we have dealt with a number of devices that implement their own custom solutions for firmware upgrading on Windows and Mac platforms.