[U-Boot] bootm command: is there any load address limitation for fdt?

Hi,

I am using u-boot version 2008.10 + git commit 13d36ec849785453953d00220b2c7dc66644a3c2

The board is a custom MPC8360E, similar to MPC8360EMDS from freescale.

My DDR-SDRAM is at address 0x0 - 0x1FFFFFFF

I am trying to limit the amount of memory needed to load and boot a linux kernel (2.6.26)

to do this I loaded my fdt at address 0x20_0000 and uImage at 0x_30_0000

When I run bootm, I both the kernel and fdt passed their checksum tests, and then I got this error.

ERROR: image is not a fdt - must RESET the board to recover.

However, if I loaded my fdt at address 0x40_0000 and uImage at 0x50_0000, bootm works fine.

Is there a reason why fdt must be loaded at a specific offset from the start of RAM?

Thank you for all your time

- Richard Retanubun.