Quote Originally Posted by Gotty101 View Post
I cant see that great on my phone, but is it that component across the pins on the microcontroller?
Yes that's right - I accidentally connected the core voltage regulation filter pin to Vss instead of the capacitor. Fortunately that pin is only connected to a capacitor, so I'm instead lifting that pin and soldering an 0402 capacitor between it and the adjacent Vss pin. Bit fiddly, but it works ...

I've not found any other mistakes yet.