USB devices don't recognized by Linux on PicoCore imx8ulp

As I guess i.MX8ULP processor has 2 USB ports, one of this is used for USB-C connector on the baseboard, The second one is connected to USB hub to make 2 USB host ports on the board.

I tried to connect USB flash drive into both host ports, but the behaviour of the system is quite stange for me: USB power is attachech for a 1-2 seconds and then disappear. Linux doesn't indicate something into a core log at all (I monitored that by "dmesg"). I wonder if It is lack of some drivers or hardware issue? I tried on two boards and two Linux images with the same results.

Update: I was able to connect USB flash drive when it was inserted before the board boots only. If I remove it during the work session it can't be attached again until the reboot. What is wrong?

USB host ports still don't work on the board. I tied to find out the problem and I made a test circuit like that:

The push button should imitate a connection of full-speed device into a host. So the test is I press the button and scope how USB communication process begins. Oscilloscope shows D+ line as yellow ans D- line as blue. There are some records from another good working hosts (NOT your board), lets see:

As you can see the host begins a communication process almost immediately after it detected D+ request.

Now lets see what happens on your board:

As you can see nothing happens. Hot plug is not detected at all.

It seems like this is a hardware issue, doesn't it?

Yes, I can provide. But since these numbers are needed to get the software, I am not sure if it is okay to share the numbers here. Please email me as an F&S employee with the request and I will reply with the board numbers.

Hello. Are there any news about the issue? I really need to develop my application with my board.