Micromax D320 VS UFi Dongle
This unit has several revisions (as far as I know 3), they differ in the eMMC chip. One firmware is not suitable for another, since eMMC support is registered in the Preloader file in the firmware itself.
In the first case, I chose the wrong firmware, if I were flashing with FlashTool, the firmware would have passed, but the phone would not turn on, since it would have a non-native Preloader. But since UFi Dongle has the “Fool Protection” system, the program warned that eMMC is not supported by this preloader and I chose the correct firmware.