Arduino for STM32

Finally got it to work! Based on 'fpiSTM' post that they got it work on the discovery board. I uploaded my code to a disco F407 and it worked immediately (luckily, I had bought one when I started working on my F407 project... it really came in handy, it's always good to have the manufacturer's dev ...

I have tried the following board variants:

[env:diymore_f407vgt]
[env:disco_f407vg]

I have a custom board with an STM32F407VGT6 that I have trying to get ports PC14/15 to work as output ports. I am using STM32Arduino with PlatformIO IDE. Setting pinMode and then doing digitalWrite has no effect on those two ports. I suspect it has to do with the fact that those pins are also used ...