Re: Possibly erroneous "device not present" message during boot

[Pascal Hambourg <pascal@plouf.fr.eu.org>]

Le 19/04/2017 à 00:27, Brian a écrit :
> On Wed 19 Apr 2017 at 00:12:15 +0200, Pascal Hambourg wrote:
>
> > Le 18/04/2017 à 21:14, Brian a écrit :
> > > However, my main point was that the kernel
> > > identifying a card as a /dev/sdX disk does not imply it will necessarily
> > > be visible to GRUB and bootable by it.
> >
> > If the card reader is idendified as /dev/sdX, then it probably behaves as a
> > generic USB mass storage device and most BIOS can see it.
>
> A card in one of the slots of my card reader is identified as /dev/sdc1.
> The reader itself is seen by lsusb. The BIOS doesn't see it and does not
> have an option to boot from it. So I suppose my reader is not "most
> BIOS". What is it behaving as?

How does lsusb identify the card reader ? What driver/module does it use 
? "lsusb -t" will tell both.

If it uses usb-storage and the BIOS can boot from a USB device, then it 
surprises me that the BIOS cannot see and boot it when it contains a 
card with proper contents.