[blfs-support] Failed to boot from USB stick

Richard Melville richard.melville69 at googlemail.com
Tue Mar 18 04:27:39 PDT 2014


On Wed, Mar 12, 2014 at 12:07 PM, Richard Melville
> <richard.melville69 at googlemail.com> wrote:
> > What worked for me in the end is the following: I don't use a initrd and
> I
> > partition the flash drive with GPT, format with ext2, and boot to an ext4
> > partition on an mSATA SSD.  I use Syslinux rather than Grub2 as it's
> lighter
> > and it's much easier (IMO) to set up.  If it's of any help here is my
> > extlinux.conf:-
> >
> > /boot/extlinux/extlinux.conf
> >    PROMPT 1
> >    TIMEOUT 50
> >    DEFAULT xxx
> >    LABEL xxx
> >             LINUX /boot/vmlinuz-3.12.8-toi
> >             APPEND root=PARTUUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx \
> >                           vga=792 acpi_osi=linux acpi_backlight=legacy
> > hest_disable \
> >                           iommu=soft rootfstype=ext4 rootdelay=1
> >
> Hi Richard,
>
> After struggling with grub, I've decided to try syslinux-6.02 with
> setup similar to yours:
> booting from usb stick with 512MB ext2 partition and ext4 root FS on
> another USB stick.
>
> I've got kernel panic - VFS: unable to mount root fs on unknown-block
> (0,0). Some forums suggests initramfs.
> I think you could skip initramfs only if you're using SATA disks. I've
> added initramfs in syslinux config, but it was unable to find a device
> containing root fs and dropped to a shell...
>
> I wonder, since you have a working setup could you try to boot your
> box with root FS on USB stick?
>
> Regards,
> Alexey
>
>
Yes, I had the same problem; you have to have the kernel image on the same
flash drive.  That could be seen as a security issue but as we are dealing
with very small computers somebody could just as easily walk off with the
complete box as they could with the USB flash drive.  Anyway, I have my USB
flash drive locked under the front cover of the case; it's not on display.
 Of course, removing the flash drive renders the computer un-bootable; a
security feature in itself.

I use an 8GB flash drive (that seems to be the optimum capacity now,
price-wise) and partition it into a 100MB boot partition with the remaining
space as swap.  With 8GB of RAM I don't need to swap to it but I'm hoping
to be able to use it for hibernation.  My systems are battery powered so I
see it as a safety feature.  I've had no luck yet getting it to work (more
BIOS problems I think) but I'm working on it.

So, the boot partition holds the extlinux directory and the kernel image
and nothing else. If you do that it should boot OK without initramfs. I've
also been able to boot to another USB flash drive so the target drive
is immaterial.  Let me know how you get on.

Richard
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