[yocto] Problem creating bootable flash

[Chris Tapp]

Hi Paul,

On 22 Mar 2013, at 07:25, Paul D. DeRocco wrote:

> I've successfully (theoretically) built core-image-base-cedartrail-nopvr. I
> plugged a 1GB eUSB SSD onto one of my USB headers, Ubuntu automounted the
> empty drive /dev/sdb1 as /media/somethingorother, I unmounted it, and then
> followed the instructions on the Yocto page for the cedartrail BSP: I used
> dd to copy the image to /dev/sdb1, synced, ejected it, and rebooted. I got
> the dreaded "Error loading operating system" from the BIOS.
> 
> Waitaminnit, I thought, isn't this image supposed to include the partition
> table, too? After all, the example given in the instructions showed the
> image being copied to /dev/sdf, not sdf1. I went back into Ubuntu, saw that
> /dev/sdb1 had been mounted as /mnt/boot_, and it contained initrd and the
> four other files. I unmounted it, and this time used dd to copy the image to
> /dev/sdb, synced, ejected it, and rebooted. This time, the BIOS wouldn't
> recognize the drive at all, so all I could do was go back into Ubuntu.
> 
> Now, Ubuntu had mounted /dev/sdb as /mnt/boot_, and it still contained the
> five files. That suggests to me that the image doesn't contain a partition
> table, and that there is now no partition table on this drive, just a single
> file system, like an old floppy. I ran parted, end it says the partition
> table type is "loop", with a single FAT16 partition running from 0.00B to
> 1028MB, the entire drive. Is "loop" just a name for an implied partition
> table that lists the entire drive, when there is no actual table?
> 
> Apparently, my BIOS (a modern Intel D2700MUD Atom mobo) looks at this USB
> drive and decides it isn't bootable. So what's the right way to do this?

I've had a few issues using the Cedartrail PRV images on an eUSB drive on an DN2800MT.

I'm not installing the same way as you:

1) I use dd to copy the hddimg to a USB stick;
2) I use this to boot the system using the 'install' syslinux item (have to be quick at boot time to catch the prompt).

Everything worked great using a mini-PCIe drive, but was failing to install to the eUSB most of the time as the drive wasn't detected - I expect it takes too long to be ready before the install script gives up. A couple of changes to the script fixed this and the image would then install.

However, it wouldn't boot. I found two issues:

1) The install script configured grub to use sdb. This was where the eUSB was when the script ran, but it's sda when used as the boot device. Another install script fixed this.
2) I also needed to add 'rootwait' to the kernel command line or else the rootfs wasn't ready at boot time, resulting in a kernel panic.

The issues with the installer are recorded in the bug tracker at https://bugzilla.yoctoproject.org/show_bug.cgi?id=4059.

It's possible that you may need 'rootwait', but I'm not sure anything else that I found is related to what you're seeing.

Can you try dd'ing the image on to a USB stick to see if that will boot? If it does, that would at least show that the image is good and it's the eUSB that is causing the pain, as it was for me.

Chris Tapp

opensource at keylevel.com
www.keylevel.com