Hi team, I’m making some deep self-learning in the Torizon architecture and BSP 3.0, and with it I arrived to the boot.src, and consequently to the FIT images and Distro Boot.
I just did a TorizonCore Yocto build and I’m trying to understand its build output as well as the booting process, although with the FIT explanation in the sheets referenced in our Distro boot knowledge base, it becomes pretty clear at least component-wise, however, I have some doubts regarding the whole process itself.
As far as I know, we migrated from the uImage (zImage + DTB) format in 2.8 to the newer ITB/Distro boot in both TEZI and Torizon. Uboot will look for the boot.src, which is mkimage’d from the ITB, which is also mkimag’ed (DTC’d) from the ITS, right?
Is the ITS file that we use with Torizon easily available to see (and change)? I’m really curious to see its structure, as I’m not completely sure the meaning of how boot.src correctly points to the DTB and kernel binary, plus the change capabilities of those. I couldn’t find it in the build output.
Related to this: How do the Uboot environment affects the booting process since the boot.src is pretty much self-contained due to the ITS meta-data? (For example if I want to change between different kernel binaries or device trees stored in the eMMC, do I have to recompile the ITS?).
Finally, I believe the ITS only contains metadata, and therefore, a kernel or device tree can still be compiled outside and simply added/changed. However I couldn’t find these binaries on the TEZI image created from Yocto (on bootfs only boot.src is found, are both contained in these? The sizes didn’t seem to match).
Sorry for the load of questions, but I couldn’t quite understand the process and I didn’t find that info in our site.
Many thanks and kind regards,
Alvaro.