Comment # 11 on bug 1103514 from Oliver Neukum

(In reply to Jose Ortega from comment #10)
> (In reply to Oliver Neukum from comment #9)
> > Please try the quirks "sf" for "usb-storage.quirks="
> > as documented in
> > https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt
> 
> Hi Oliver.
> 
> I'm sorry as I'm a home user and not really an expert in these kind of
> things, so I have some doubts regarding what to do, at first I thought about
> adding "usb-storage.quirks=sf" as a kernel parameter when booting, but the
> documentation explains another thing entirely in the example, and I quote:
> 
> quirks=0419:aaf5:rl,0421:0433:rc
> 
> so I'm not sure which one to do.

Sorry 

usb-storage.quirks=2109:0711:sf

You need to tell the kernel which devices the quirk is for (by product and
vendor id) and the quirk.

If it does not work dmesg and udevadm monitor -kup please.