well... this is _sort_ of progress... a 1.5k resistor is missing from the USB+ line on the STM32F, which, when added, resulted in the exact same error being created when the exact same software was uploaded to the Port103R demo board.
at this point it can be reasonably concluded that the STM32F software being uploaded to both boards, to get USB working, is shagged. which is odd, because i had it working a few weeks back [on the Port103R].
l.
Oct 2 16:05:41 localhost kernel: [2829651.641936] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 Oct 2 16:05:41 localhost kernel: [2829651.641943] usb 1-1.4: Product: HID Demo Oct 2 16:05:41 localhost kernel: [2829651.641948] usb 1-1.4: Manufacturer: Black Sphere Technologies Oct 2 16:05:41 localhost kernel: [2829651.641953] usb 1-1.4: SerialNumber: DEMO Oct 2 16:05:41 localhost kernel: [2829651.643699] input: Black Sphere Technologies HID Demo as /devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1.4/1-1.4:1.0/input/input55 Oct 2 16:05:41 localhost kernel: [2829651.643903] generic-usb 0003:0483:5710.0030: input,hidraw7: USB HID v1.00 Mouse [Black Sphere Technologies HID Demo] on usb-0000:00:1d.7-1.4/input0 Oct 2 16:05:42 localhost kernel: [2829652.924274] usb 1-1.4: reset full-speed USB device number 72 using ehci_hcd Oct 2 16:05:42 localhost kernel: [2829652.996291] usb 1-1.4: device descriptor read/64, error -32 Oct 2 16:05:42 localhost kernel: [2829653.172291] usb 1-1.4: device descriptor read/64, error -32 Oct 2 16:05:42 localhost kernel: [2829653.348275] usb 1-1.4: reset full-speed USB device number 72 using ehci_hcd Oct 2 16:05:42 localhost kernel: [2829653.420284] usb 1-1.4: device descriptor read/64, error -32 Oct 2 16:05:43 localhost kernel: [2829653.596291] usb 1-1.4: device descriptor read/64, error -32 Oct 2 16:05:43 localhost kernel: [2829653.772290] usb 1-1.4: reset full-speed USB device number 72 using ehci_hcd Oct 2 16:05:43 localhost kernel: [2829654.180018] usb 1-1.4: device not accepting address 72, error -32 Oct 2 16:05:43 localhost kernel: [2829654.252288] usb 1-1.4: reset full-speed USB device number 72 using ehci_hcd Oct 2 16:05:44 localhost kernel: [2829654.660048] usb 1-1.4: device not accepting address 72, error -32 Oct 2 16:05:44 localhost kernel: [2829654.661392] usb 1-1.4: USB disconnect, device number 72 Oct 2 16:05:44 localhost kernel: [2829654.760280] usb 1-1.4: new full-speed USB device number 73 using ehci_hcd Oct 2 16:05:44 localhost kernel: [2829654.832266] usb 1-1.4: device descriptor read/64, error -32 Oct 2 16:05:44 localhost kernel: [2829655.008394] usb 1-1.4: device descriptor read/64, error -32 Oct 2 16:05:44 localhost kernel: [2829655.184394] usb 1-1.4: new full-speed USB device number 74 using ehci_hcd Oct 2 16:05:44 localhost kernel: [2829655.256412] usb 1-1.4: device descriptor read/64, error -32 Oct 2 16:05:44 localhost kernel: [2829655.432267] usb 1-1.4: device descriptor read/64, error -32 Oct 2 16:05:45 localhost kernel: [2829655.608391] usb 1-1.4: new full-speed USB device number 75 using ehci_hcd Oct 2 16:05:45 localhost kernel: [2829656.016073] usb 1-1.4: device not accepting address 75, error -32 Oct 2 16:05:45 localhost kernel: [2829656.088262] usb 1-1.4: new full-speed USB device number 76 using ehci_hcd Oct 2 16:05:46 localhost kernel: [2829656.496048] usb 1-1.4: device not accepting address 76, error -32 Oct 2 16:05:46 localhost kernel: [2829656.496420] hub 1-1:1.0: unable to enumerate USB device on port 4