This method is tested and working with Intel's USB3.0 controller under Windows 8.1 x64. Possibly works on other RK3188 devices under Windows 8.1. 1. Download Intel(R)_USB_3.0_eXtensible_Host_Controller_Driver_MOD.zip and extract it. 2. Reboot windows with driver signature disabled: configure->change pc settings-> update & recovery -> recovery-> advanced startup -> troubleshoot -> advanced options -> restart -> 7 3. Open Windows Device Manager, Go to Universal Serial busses at the end and double click “Intel USB 3.0 eXtensible controller”. Click on Drivers in the New window which opens. 4. Now click “Update Driver” and then select “Browse my computer for driver software”. Next choose “Let me pick from a list of device drivers on my computer” and select “Have Disk”. 5. In the Window that pops up titled “Install From Disk” choose “Browse” and navigate to location “Intel(R)_USB_3.0_eXtensible_Host_Controller_Driver_MOD\Drivers\Win7\x64″. Select "iusb3xhc.inf" and click ok. Ignore all warnings and install the drivers. 6. After installing, Reboot the computer with the same procedure as Step 2. 7. Open Windows Device Manager again, you should see an Unknown device. 8. Right Click on it and choose “Update Driver” then click “Browse my computer” and then “Let me pick from a list of device drivers on my computer”, scroll down and select “Universal Serial Bus Devices”. 9. Click next, choose “Have Disk”, “Browse” and select the "iusb3hub.inf". Ignore all warnings and install the drivers. 10. Reboot your PC as normal. 11. Install Rockchip Drivers if you haven't. You may have a yellow (!) or (?) on M9Pro drivers in Device Manager but RKtool works just fine.