U-Boot> boot
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
No FDT memory address configured. Please configure
the FDT address via "fdt addr <address>" command.
Aborting!
4890184 bytes read in 9201 ms (518.6 KiB/s)
Kernel image @ 0x1000000 [ 0x000000 - 0x4a9e48 ]
ERROR: Did not find a cmdline Flattened Device Tree
Could not find a valid device tree
U-Boot> printenv bootcmd
bootcmd=run setup; run loadkernel; bootz ${kernel_addr_r} - 0x100
U-Boot> printenv setup  
setup=fdt addr 0x100; fdt get value bootargs /chosen bootargs
U-Boot> fdt addr 0x100
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
U-Boot>