IMX8MM - device tree overlay - unable to load .dtb and .dtbo in uboot

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IMX8MM - device tree overlay - unable to load .dtb and .dtbo in uboot

Contributor I

overlay - unable to load .dtb and .dtbo


I am using iMx8mm board and I have created .dtbo(device tree blob overlay ) file and copied it in /lib/firmware and .dtb (deivce tree blob ) file boot partition when I am doing load of .dtb and .dtbo file it giving error like

** Reading file would overwrite reserved memory **

I have attached screenshot of u-boot . Please guide what's my mistake here ,



I am following this process to load .dtbo and .dtb which is avialable at uboot/uboot_version/git/doc/README.fdt-overlays

Manually Loading and Applying Overlays

1. Figure out where to place both the base device tree blob and the
overlay. Make sure you have enough space to grow the base tree without
overlapping anything.

=> setenv fdtaddr 0x87f00000
=> setenv fdtovaddr 0x87fc0000

2. Load the base blob and overlay blobs

=> load ${devtype} ${bootpart} ${fdtaddr} ${bootdir}/base.dtb
=> load ${devtype} ${bootpart} ${fdtovaddr} ${bootdir}/overlay.dtb

3. Set it as the working fdt tree.

=> fdtaddr $fdtaddr

4. Grow it enough so it can 'fit' all the applied overlays

=> fdt resize 8192

5. You are now ready to apply the overlay.

=> fdt apply $fdtovaddr

6. Boot system like you would do with a traditional dtb.

For bootm:

=> bootm ${kerneladdr} - ${fdtaddr}

For bootz:

=> bootz ${kerneladdr} - ${fdtaddr}

Please note that in case of an error, both the base and overlays are going
to be invalidated, so keep copies to avoid reloading.ubootuboot

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3 Replies

Contributor IV

Hi @Gourav,

We have achieved DTBO implementation on imx8mm with kirkstone build at Silicon Signals Pvt. Ltd.
Connect in case of discussion at

Rutvij Trivedi

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NXP TechSupport
NXP TechSupport

Thank you for contacting NXP support!

Sorry, we don't have any examples for Device Tree Overlays.

You can follow the U-boot documentation:

Device Tree Overlays — Das U-Boot unknown version documentation

We normally use the command fatls mmc x:x to obtain a list of the dtb files available and change it with the next commands

u-boot=> setenv fdtfile <name>.dtb                      
u-boot=> saveenv

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NXP TechSupport
NXP TechSupport



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