I did my own board with STM32F429IGT6, and connect the ST-Link v3 using the ST-Link Utility. "No target detected".

[j.p.mateos]

Previously I had made boards, and the basic connection is Vcaps to 2.2uF capacitors, nRst with 10k pull-up, and Boot to ground. The device is not detected by the programmer.

[Tesla DeLorean]

The error is indicative that the part is non-functional, or the debug interface is wired wrong.

Check voltage level on VCAP pin, and also NRST pin.

Check part orientation.

Secondary means of checking signs of life would be to pull BOOT0 High, and using USART1 at 9600 8E1 (Per App Note AN2606).

Send an 0x7F character, and see if device responds with an 0x79

[andy2399]

You need to bring out and connect RESET to ST-Link along with SWDIO and SWCLK.

Andy

[j.p.mateos]

Must connect BYPASS pin to ground, to activate internal regulator, and have the correct voltage at VCAP.

That will make it run.

[NCard]

"No target detected" after a hard day a simple cable DIO was interrupted,