“Device Tree In Memory
The kernel has 2 ways it can find a device tree in memory. The 1st and industry standard method is that it expects the address of the device tree to be in register R2 when the boots. Starting in 14.3 this is the default kernel configuration, but it was not previously.

The 2nd method, and the default in the Xilinx kernel configuration, is hard coded such that it expects the device tree at address 0x1000000 (16 MB). This is referred to as Device Tree At Fixed Address in the kernel configuration. The purpose of the fixed address for a device tree is to allow the go command in u-boot (which does not set up R2 to point to the device tree) to continue to be used.

This method can be enabled in the kernel configuration and must be disabled if a device tree is to loaded at other addresses while using the bootm command in u-boot.
Note that the Device Tree At Fixed Address kernel configuration option is only available in the menu when device tree has been enabled in the kernel configuration.”