search for: ehci_gadget_debug

...rg/EHCI_Debug_Port It is already used in the linux kernel and there is also a linux module that acts as a debug monitor/device on the other side. So you can use your linux workstation to get those logs. https://www.kernel.org/doc/Documentation/x86/earlyprintk.txt and http://www.coreboot.org/EHCI_Gadget_Debug bye roman