I have a Quectel Modem on my PCB that connects to the NXP 6ULL processor via USB. I power the modem from a 3.3V converter and I do not use the VBUS processor.
Where to connect VBUS pin because it is important for communication and the kernel does not see the USB device. Now it's floating.
The modem works and is properly powered because I have communication via UART. Error is definitely related to the VBUS line as kernel bugs indicate this.