Unable to connect and flash program to STM32F407(custom board)

[Cpatt.1]

  1)is crystal is required to be used for program flashing 

2) boot0 to be low or High

Note: I'm using ST-LINK V2

[Tesla DeLorean]

It doesn't need an external crystal as it runs from HSI.

The BOOTx pin shouldn't make a lot of difference unless the user code sleeps the device or reconfigures pins.

M​ore likely you're not powering it properly, issues with VDDA or VCAP

[MM..1]

How stlink you use explain SWD connection show photo...