How to enlarge the shared-dma-pool on orin?

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Orin
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Platform:Jetson AGX Orin on custom carrier, R35.6

Hi,I am trying to enlarge cma size on orin, but after I changed the cma size in the dtb, after i recompiled and replaced the dtb, it doesn’t work, it seem like the cma size is limited to 512M.
The cma node in dtb:

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linux,cma{
compatible = “shared-dma-pool”;
reusable;
size =<0x00 0x20000000>;
alignment =<0x00 0x10000>;
linux,cma-default;
status = “okay”;
};

I change the size property like this:
size =<0x00 0x80000000>;
or
size =<0x00 0x40000000>;

even I change the size from 512M to 2GB or other size,
when I use command ‘dmesg’,the kernel message shows the same result that the cma is 512M:
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[.000000 ]Reserved memory: created CMA memory pool at 0x00oo000df6800000，size 512 MiB
[0.000000] OF: reserved mem: initialized node linux,cma，compatible id shared-dma-pool

Do you know how to enlarge the share-dma-pool?

Thanks!