working dts and bt

dts/README.md

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+# Rebuild dts tree fo MQ pro..
+
+see: https://manpages.ubuntu.com/manpages/focal/man1/dtc.1.html
+
+## Notes for re-generating MQ PRO device tree (`.dtb`)
+My notes
+* By default the Device Tree compiler (`/usr/bin/dtc`) should already be installed, as should the linux-headers for the kernel.
+
+### compile the mq-pro dts with the current kernel headers
+Example here is against the 'default' 6.8.0-31 linux kernel from the Ubuntu 24.04 release
+* clean the `dtspp` folder: `rm dtspp/*`
+* edit and run `bake.sh` to precompile the files against the latest linux-headers
+* cd into the `dtspp` folder and run: 
+  `dtc sun20i-d1-mangopi-mq-pro.dts > dtb-6.8.0-31-mqpro`
+  modify the version to reflect the current headers
+* move the `.dtb` file into the `/boot` folder:
+  `sudo mv dtb-6.8.0-31-mqpro /boot/dtbs`
+* make a link in `/boot` to this:
+  `sudo ln -s dtbs/dtb-6.8.0-31-mqpro /boot/dtb-mqpro`
+
+### Set up Grub to test boot the new DTB
+Initially we will test the new dtb:
+* backup the grub config: `sudo cp /etc/grub/grub.cfg /etc/grub/grub.cfg.generic-dtb`
+* `sudo vi /etc/grub/grub.cfg`  (or use nano if you prefer)
+  Find the 1st `menuentry` section (the default Ubuntu one) and edit the `devicetree` line to look like:
+  `devicetree      /boot/dtb-mqpro`
+* Reboot (`sudo reboot`) (remember the mq-pro is sloooow to reboot ;-) )
+* If the reboot fails you can either attach a serial adapter to the GPIO pins and select the fallback kernel from the advanced options menu, and then restore the grub config backup once logged in. 
+  Or (if no serial available) remove the SD card, mount it on another computer and restore the file there.
+
+### Check that we have the correct device tree
+`dtc -I fs /sys/firmware/devicetree/base | grep 'model'`
+* ignore all the 'not a phandle reference' warnings
+* you should see `model = "MangoPi MQ Pro"` at the end
+
+### Make this permanent in grub
+ToDo
+
+