Just a bit of arcane knowledge on compile of a kernel: The “O=/some/file/path” is used when building a kernel with temporary files and output in an alternate location. Normally this would be optional, but some changes were made in R28.1 kernel source layout when both the TX1 and TX2 started using the same source. The R28.1 documentation under kernel customization explains which must be used. See (search for “Documentation”):
[url]https://developer.nvidia.com/embedded/linux-tegra[/url]