Makedts is bash script that invokes the C preprocessor and device-tree compiler to transform a nested hierarchy of device-tree source files into a single human-readable ASCII output. Many mistakes in DTS are obvious from inspection of the script's output: some node is at the wrong level of the hierarchy, or has an empty property that was expected to be populated. A working similar device-tree binary can be compared by running fdtdump (in the kernel source's scripts/dtc) on the binary and lining up the forward-compiled failure with the reverse-compiled working DTB.
makedts produces a similar result to fdtdump's output on a matching DTB, but with the advantage of having ASCII-formatted strings rather than hex ones.
See previous discussion at https://lwn.net/Articles/573409/ and http://www.spinics.net/lists/devicetree/msg08941.html.