Re: nativedisk not working in 2.0.4

[Brian J. Murrell]

On Mon, 2020-11-23 at 10:06 -0500, Brian J. Murrell wrote:
> I am using grub2-pc version 2.0.4 as packaged by Fedora 32.
> 
> I am trying to get a serial console working using a USB->Serial
> dongle.
> 
> I understand that in order to do that I need to use GRUB's native
> drivers as the moment GRUB tries to use the USB hardware it loses use
> of the BIOS disk drivers.
> 
> Working at a command-line for the moment, to figure out the steps I
> do:
> 
> grub> insmod nativedisk
> grub> nativedisk
> error: ../../grub-core/net/net.c:1547:disk `hd0,msdos1' not found.
> error: ../../grub-core/net/net.c:1547:disk `hd0,msdos1' not found.
> error: ../../grub-core/net/net.c:1547:disk `hd0,msdos1' not found.
> error: ../../grub-core/net/net.c:1547:disk `hd0,msdos1' not found.
> error: ../../grub-core/net/net.c:1547:disk `hd0,msdos1' not found.
> error: ../../grub-core/net/net.c:1547:disk `hd0,msdos1' not found.
> error: ../../grub-core/net/net.c:1547:disk `hd0,msdos1' not found.
> error: ../../grub-core/net/net.c:1547:disk `hd0,msdos1' not found.
> error: ../../grub-core/net/net.c:1547:disk `hd0,msdos1' not found.
> error: ../../grub-core/net/net.c:1547:disk `hd0,msdos1' not found.
> 
> and then am left with a frozen grub> prompt.  Even ALT-CTRL-DEL
> doesn't
> work.

Maybe what is really quite relevant but had only occurred to me this
morning is that the disk that the machine is booted on is a SD-Card
which is connected by USB:

Bus 001 Device 004: ID 0bda:0159 Realtek Semiconductor Corp. RTS5159 Card 
Reader Controller

I suppose nativedisk cannot support that as it needs the USB drivers
loaded also, (at least) and the moment you load those, you lose access
to the disk through the BIOS.

Can the USB modules be loaded but left in an "un-activated" state so
that they don't interfere with BIOS access to the USB disk?  Once they
are all loaded, then nativedisk can "activate" the USB drivers (which
are already loaded, but inactive) to get access to the disk.

Is this possible?

But maybe this is what is supposed to happen already?

https://wiki.debian.org/BootUsbWithGrubRescue#Booting_a_flash_drive_with_an_image_file_written_to_it
#3 says:

   Use the nativedisk command to tell Grub to load its native disk and
   USB drivers.

Which seems to be implying that the nativedisk command is loading the
USB drivers also.

Cheers,
b.

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