reason H745 not booting

[SHanl.1]

Hi,

I have a custom board with an STM32H745 which doesn't boot / I can't connect to.

I've noticed that three of the gnd pins are not connected K15, L15, M15, would this cause the problem?

The design is using an external 1.2V supply which is fine. 3.3V is also fine.

I'm seeing 1.2V on the reset pin.

Any thoughts?

[Uwe Bonnes]

Unconnected power pins may caus all kind of headaches. Fix that. Check also power sequencing requirements.

[TDK]

All power pins are required. The chip will not run without them connected.