Raspberry Pi USB unstable issue with external USB devices

Some kernel parameters for fix Raspberry Pi USB issues. (Source: StackExchange)

dwc_otg.speed : 1 will limit USB speed to full speed 12Mbps (USB 1.1)

dwc_otg.lpm_enable : 0 by default, it disalbes LPM support, never seen anyone with value 1 here but it’s specified in default cmdline.txt

dwc_otg.fiq_fix_enable : 1 (default now) give about 10% extra performance to ARM when USB is not busy by lowering the number of interrupts USB does

dwc_otg.microframe_schedule : 1 (default now) This should fix the error when too many periodic endopoints are present

dwc_otg.nak_holdoff_enable : 1 (default now) NAK holdoff schame, don’t really know what it does

does that work?

dwc_otg.fiq_fix_enable : 1

Seems this will fix the USB unstable issue, but not completely.