On Sun, 2016-02-07 at 19:50 -0800, Vagrant Cascadian wrote: > On 2016-02-06, Heinrich Schuchardt wrote: > > Booting with u-boot-imx requires imx6q-wandboard-revb1.dtb. > > linux-image-4.3.0-1-armmp installs imx6q-wandboard.dtb > > leaving me with a system that will not boot. > > > > With imx6q-wandboard-revb1.dtb the system boots. > > As you've noted, flash-kernel has no way of distinguishing which variant > to support, though u-boot does. I've sometimes wondered weather u-boot > should pass a boot argument for which .dtb to use... > > To make matters worse, in older versions of the linux kernel, such as > the 3.16.x in jessie, imx6q-wandboard.dtb may actually be for wandboard > revb variants, not for the revc variants (although I have one of each, > both running the same .dtb in jessie without obvious problem, though I > don't make use of the wifi or bluetooth on either). > > When the revc was added, backwards compatibility was broken by renaming > the revb .dtb file instead of keeping it and introducing the revc in a > new .dtb... kind of hard to fix correctly now... > > Adding support for flash-kernel to copy multiple, or even optionally all > .dtb files could at least work around the issue.
flash-kernel's DTB entry can reference a script to run which prints the DTB filename to use, so if you can distinguish the variants by poking at /sys etc (e.g the current sole user is kirkwood-qnap which looks at properties of the PCI host bridge etc) then that might be an option? Were any of these boards supported in Jessie? If so then making upgrade work smoothly would be nice, but if not then this might just be a case of Testing/Unstable users having occasionally to manually fix things, but once this is done and the correct DTB is in use flash-kernel should form then on DTRT and Stretch will just work for fresh installs. Ian.
