Hello Stephen,
Prior the to kbuild conversion, U-Boot used to produce file u-boot.dtb in the root of the object tree. Now it doesn't, but I think puts the same file in dts/dt.dtb instead. Was this a deliberate change?
The patch is already on Patchwork and I think it should be applied soon. Sorry for the inconvenience.
We have some flashing utilities that build U-Boot, then copy this result file. This utility no longer works because the file it's looking for no longer exists. I'd rather fix the U-Boot build process so its output filenames don't change, than fix the utility to look for a variety of different output filenames. Are you OK with a patch reverting the output filename change?
Related, I also found that pre-Kbuild, I could "make BUILD_DIR=...", but now I have to "make O=...". That's also an external change in behaviour. Was that intentional?
"make O=..." are always supported before and after Kbuild. (I guess many peaple use it for less typing.)
And yes, "BUILD_DIR" was replaced with "KBUILD_OUTPUT" when I impored many build scripts from Linux Kernel.
All overridable variables in Kbuild are prefixed with "KBUILD_", so I am following this rule. I hesitate to rename only KBUILD_OUTPUT inconsistently.
Best Regards Masahiro Yamada