Re: Official way of enabling USB on grub 2.02?

[Andrei Borzenkov]

В Sat, 10 Jan 2015 06:14:02 +0100
adrian15 <address@hidden> пишет:

> El 09/01/15 a las 07:10, Andrei Borzenkov escribió:
> > В Fri, 09 Jan 2015 02:45:40 +0100
> > adrian15 <address@hidden> пишет:
> >
> >> I'm having problems using my old commands (from grub 2.00) for enabling
> >> USB when using grub 2.02. I also think that in grub 2.00 they did not
> >> work completely ok.
> >>
> >> Anyways, the question is:
> >>
> >>     How one is supposed to enable Grub2's USB support when using: 2.02?
> >>
> >> I'm currently doing my tests with Debian Jessie: 2.02~beta2-19 version.
> >>
> >>
> >>
> >> These were the original commands:
> >>       insmod ohci
> >>       insmod uhci
> >>       insmod usbms
> >>       update_paths
> >>
> >> The first one says:
> >> error: disk `hd96' not found
> >>
> >
> > USB drivers work with hardware directly and so conflict with BIOS
> > for hardware access. For this reasons as soon as you load any driver
> > that does it grub will stop calling into BIOS. As by default grub is
> > using BIOS for hard drive access, those devices no more work.
> Ok. I can understand it.
> 
> But why every command at grub shell (even: echo $grub_prefix) after 
> running: "insmod ohci" always says:
> 
> error: disk `hd96' not found.
> 

Because $prefix still refers to old disk that does not exist anymore.
nativedisk command takes care of rediscovering device using new drivers
and redefines $prefix accordingly.