On Thu, 2014-05-22 at 08:24 -0500, Dennis Gilmore wrote:
u-boot 2014.04 added an option to the syslinux config support for a fdtdir entry which is a directory where u-boot can find the dtbs it relies on the platforms u-boot having a variable fdtfile to know which file to load for the platform
Thanks, this is looking like something which might actually motivate this sort of change.
Although the extlinux.conf entry is itself distro specific and could easily refer to a distro specific path.
the syslinux config file is looked for in /boot/extlinux/extlinux.conf and /extlinux/extlinux.conf
contents is
timeout 20 totaltimeout 9000
default=Fedora (3.15.0-0.rc5.git2.9.fc21.armv7hl) 21 (Rawhide) label Fedora (3.15.0-0.rc5.git3.1.fc21.armv7hl) 21 (Rawhide) kernel /vmlinuz-3.15.0-0.rc5.git3.1.fc21.armv7hl fdtdir /dtb-3.15.0-0.rc5.git3.1.fc21.armv7hl/ append console=ttymxc0,115200 root=UUID=7ee85ed8-de4a-4779-8658-2daed0d35e97 ro rhgb quiet LANG=en_US.UTF-8 initrd /initramfs-3.15.0-0.rc5.git3.1.fc21.armv7hl.img
label Fedora (3.15.0-0.rc5.git2.9.fc21.armv7hl) 21 (Rawhide) kernel /vmlinuz-3.15.0-0.rc5.git2.9.fc21.armv7hl fdtdir /dtb-3.15.0-0.rc5.git2.9.fc21.armv7hl/ append console=ttymxc0,115200 root=UUID=7ee85ed8-de4a-4779-8658-2daed0d35e97 ro rhgb quiet LANG=en_US.UTF-8 initrd /initramfs-3.15.0-0.rc5.git2.9.fc21.armv7hl.img
So in theory you can pull a sdcard or hdd from one machine and boot it in another, in practice as so many vendors do not ship u-boot on some kind of local storage you need to put the right u-boot into the disk first.
Yes, that is a bit of a pain isn't it. Often in these cases I suspect the u-boot end (presumably containing $fdtfile) is on the sdcard too.
Ian.