My Android smartphone no longer was recognized. many many hours over many days trying to solve this... and gave up. [but not really, it keeps nagging...]
Now i finally understand.
This cable is what i used to connect my USB3 / card reader frontpanel to said header on the motherboard(s).
Everything worked in the past with this frontpanel, when i still had it plugged in to the traditional USB 3 Gen 1 header at the bottom of the motherboard(s). But that place is too close to the bottom PCI-e slot where i have my audio card. I already broke one frontpanel's usb plug, so i decided to finally start using the motherboard's USB 3.1 Gen 2 header.
I had to buy the abovementioned cable. (I actually did not buy it at amazon, i bought it here at HighFlow).
But the description at amazon article has in the end given me the final answer.
This explains why the Android phone (which has USB-C shaped out plug but uses in fact a USB 2.0 connection through its original Samsung USB-C shaped to USB 2 cable, cannot be recognised through that header, thus through the entire frontpanel. Only the charging works through those USB ports.for ASUS Motherboard . Only support usb3.1/usb3.0 device, it can't work at USB2.0(480Mbps)
Too bad. All other devices work: my USB 3 sticks, my camera's SDHC cards etcetera.
So for transferring pictures from my smartphone to PC i now use an external USB 3 bay connected to a backside external USB 3.0 port on my PC, works fine.