funnily enough if i connect the unpowered board i get 
```
[24903.815627] usb 1-2.4.1: new full-speed USB device number 108 using xhci_hcd
[24903.919898] usb 1-2.4.1: New USB device found, idVendor=0483, idProduct=df11, bcdDevice=22.00
[24903.919902] usb 1-2.4.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[24903.919904] usb 1-2.4.1: Product: STM32  BOOTLOADER
[24903.919906] usb 1-2.4.1: Manufacturer: STMicroelectronics
[24903.919907] usb 1-2.4.1: SerialNumber: 206E38933232
```