Hi,
Same here!
I burned my M5DINMeter both with UIFlow2 and M5Burner, version 2.0.4 (and also 2.0.3 to test) with Mac first, then Windows (tried several USB cables), and also with option "direct startup on main.py" and "Show startup menu etc.".
My M5 DIN Meter does nothing.
On USB, it wakes up (red light on back) nothing on the screen.
On battery, a long press on the encoder wakes up (red light on back) nothing on the screen.
One good news: UIFlow2.0 detects when it is on, so the wifi works and is well configured.
Sending program through UIFlow2 with buttons "Run" or "Download the program to the device" shows a toaster notification on UIFlow2 screen saying that everything is successful. Still does nothing on the M5DINMeter, even after reset / long press on encoder / any short or long press on StampS3's button.
I tried 2 programs: 1 Hello World, and another doing 1 short beep every second (I though the screen was broken).
Another good news: I tried the Arduino IDE with official board & libraries support: all examples work well (even with warnings about usage of deprecated functions). Libraries: M5Core2 + M5DINMeter coming with a lot of dependencies.!
One last thing: DinMeter Demo.exe works well to reset the device to factory state.