As far as I see comment#75 looks exactly as it should look when the CUPS backend 'usb' successfully decetcts an USB printer. Therefore I wonder what the problem is now? The bug's current subject reads: "... CUPS backend 'usb' sometimes no longer detect USB printers ..." To debug that isuse we need degugging output for the case when it happens that the CUPS backend 'usb' does NOT detect the printer.