Sebastian

Hello @tooz Thank you very much for your support. I was able to build the dtbo file and apply the overlay successfully. Actually, what really helped me was to understand how I validate the deactivation by evaluating the existance of /sys/devices/platform/ffa30000.gpu. (and /sys/devices/platform/wireless-wlan resp.) dmesg | grep -i overlay still returns nothing, even when the overlay is successfully applied. With this knowledge I re-evaluated my former dts files - the first one already worked. Once again: Thanks. This helped me to solve my issue.

Good morning, I am working with the Tinker Board S for a customer project and need to deactivate components for production as a security and perfomance measure. For example, I want to deactivate the GPU and and WiFi via device tree overlays as a low level approach to accomplish this goal. I saw that you shiped several overlays and found a couple of entries in this forum about overlays making me believe that this is the approach to go. Unfortunately, I was not able to succeed so far. What I did: 1. tested to compile the three attached overlays. compilation with dtc -O dtb -o disable-gpu.dtbo -b 0 -@ disable-gpu-overlay.dts worked fine. I move the file disable-gpu.dtbo to /boot/overlays and added them at the end of /boot/config.txt (overlay=disable-gpu) but the overlay seems not to be loaded, because GPU and Desktop still booting and: dmesg | grep -i overlay returns nothing -> no overlays loaded 2. Next approach was to load it manually, but "dtoverlay" is not installed (should be included into device-tree-compiler package) 3. As an alternative I wanted to decompile the dtb and change the activation status directly there or apply the overlays manually to the dtb. But I do not find any *.dtb file in the filesystem. Could you please point me to the best way to accomplish my overall goal and walk me through the process? Thank you in advance! disable-gpu-overlay_approach1.dts disable-gpu-overlay_approach2.dts disable-gpu-overlay_approach3.dts deviceTreeOutput.txt config.txt