Device Tree change not reflected in final image

[_Krishna]

 

Hello,

I am working on STM32MP2 using the OpenSTLinux Weston distro and I am modifying the OP-TEE/device-tree files under the external-dt workspace using devtool.
I need to remove a pin definition from the CA35 OP-TEE DTS files, but even after rebuilding the image, the pin still appears in the running system:

 

 

line 8: "PI8" input consumer="kernel"

 

This means my change was not applied.

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Steps I followed

1. Environment setup

 

 

DISTRO=openstlinux-weston MACHINE=stm32mp2-rt source layers/meta-st/scripts/envsetup.sh

 

2. Opened the external-dt workspace

 

 

devtool build external-dt cd build-openstlinuxweston-stm32mp2-rt/workspace/sources/external-dt/

 

3. Edited the following DTS files to remove a tamper-related pin

Files I modified and added to git:

• stm32mp2/a35-td/optee/stm32mp257f-ev1-ca35tdcid-ostl-m33-examples.dts

• stm32mp2/a35-td/optee/stm32mp257f-dk-ca35tdcid-ostl-m33-examples.dts

• stm32mp2/a35-td/optee/stm32mp257f-ev1-ca35tdcid-ostl.dts

• stm32mp2/a35-td/optee/stm32mp251f-ev1-ca35tdcid-ostl.dts

• stm32mp2/a35-td/optee/stm32mp257f-ev1-ca35tdcid-ostl-m33-examples-sram.dts

• stm32mp2/a35-td/optee/stm32mp257f-dk-ca35tdcid-ostl.dts

• Also committed the corresponding *.orig files

4. Staged and committed using devtool workspace git

 

 

git add <all modified files> git commit -m "tamp removed"

 

The commit succeeded:

 

 

[devtool 860e32d] tamp removed 8 files changed, 16 insertions(+), 16 deletions(-)

 

5. Rebuilt the image

 

 

bitbake st-image-core

The build completed successfully.

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Problem

Even after rebuilding:

• The pin PI8 still shows up in the system as:

   

  "PI8" input consumer="kernel"

• Meaning the DTS change did not make it to the final DTB.

• I confirmed the DTS files were edited correctly.

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Question

What additional steps are needed to ensure:

1. The modified DTS files inside external-dt are actually used by U-Boot / Kernel / OP-TEE?

2. How do I verify which DTS → DTB is consumed during boot?

3. Do I need to clean the kernel or u-boot sstate for OP-TEE related DTS changes?

4. Why does devtool show that patches were applied, but the final filesystem still shows the original pin?

Any guidance on how to correctly regenerate the final DTBs for STM32MP2 with OP-TEE device-trees would be helpful.

Thank you!