HP Microserver Gen8 USB2.0 not working in ESXi5.5/6.0/6.5

I'm completely lost.

When installing HPE customized ISO/Image for their Microserver Gen8 the USB2.0 (or legacy so you want) are not recognized within ESXi and therefore not working. The only two USB3.0 ports are working well. Since I want more USB devices to be connected it would be nice the other four external USB2.0 ports should work too.

What I've done so far:

- Updated the machine firmware with the HPE SPP package

- Tried ESXi5.5U3 (HPE customized ISO)

- Tried ESXi6.0 (HPE customized ISO)

- Tried ESXi6.5 (HPE customized ISO)

- Tried ESXi6.5U1 (HPE customized ISO)

- Disable USB3.0 controller in the BIOS so maybe USB2.0 should work. Unfortunately not.

- Tried Important information about the new ESXi 6.5 USB driver vmkusb, and the legacy USB drivers (2147650) | VMware KB

- EHCI handoff BIOS setting (not available)

Nothing of the above seems to be a solution

If an USB device is connected into a USB2.0 socket it works (LEDs blinking etc.) until the hypervisor starts. So my conclusion (must be) is has to be ESXi or driver related.

Hope anyone can help me out.