[blfs-support] Failed to boot from USB stick

Bruce Dubbs bruce.dubbs at gmail.com
Tue Mar 18 10:16:16 PDT 2014

Alexey Orishko wrote:
> On Tue, Mar 18, 2014 at 12:27 PM, Richard Melville
> <richard.melville69 at googlemail.com> wrote:
>> 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.
> I have a few SATA disks connected to motherboard in addition to USB
> boot disk, so I'm using UUID to identify root partition.
> I have to use initramfs because I refer to root fs via UUID and udev
> is not running at the time of mounting root fs.
> So far with extlinux I could boot to ram disk on the new BIOS (where
> grub fails miserably).
> However on all motherboards boot process stops at the point of
> mounting/finding  root partition.
> I do have a rootdelay, but it does not help:
> LABEL MyLinux
>      menu label MyLinux
>      LINUX /boot/vmlinuz-3.10.32-sm01
>      APPEND root=PARTUUID=49acd73e-1457-424f-8dc1-3c3fa027becf \
>                    rootfstype=ext4 rootdelay=20
>      INITRD /boot/initrd.img-3.10.32-sm01
> If I do blkid, I can see /dev/sdh1 with a correct UUID (root fs).
> I suspect initramfs image might have some issues and I wonder if I can
> use scripts from BLFS or CLFS to create it or I need some adjustments
> for extlinux variant (for example, /boot is a separate partition now).

If you are using a GUID Partition Table (GPT), then you don't need a 
initrd.  Assuming /boot is on a partition by itself, try:

menuentry "LFS Dev, Linux 3.10.32-sm01" {
    linux /vmlinuz-3.10.32-sm01 \
      root=PARTUUID=49acd73e-1457-424f-8dc1-3c3fa027becf \
      rootfstype=ext4 rootdelay=20

Of course, grub needs to be able to find the partition with the kernel 
on it.  It should be on the boot device with where grub.cfg is located.

   -- Bruce

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