Add Devicetree To Grub Automatically: Here's How

[The Tall Man]

This will cause update-grub to add the following a devicetree line to all menu entries. This example is based on Debian Trixie's grub-efi.

 

This example will expect dtb directories (or links) to be in the /boot directory, using the convention that I've seen Armbian use. Here is an example of a /boot directory listing for (pure) Debian Trixie with two kernels:

-rw-r--r-- 1 root root   336036 Aug 27 04:10 config-6.12.43+deb13-arm64
-rw-r--r-- 1 root root   343394 Sep  6 12:48 config-6.16.3+deb13-arm64
lrwxrwxrwx 1 root root       42 Sep 20 16:17 dtb -> ../usr/lib/linux-image-6.16.3+deb13-arm64/
lrwxrwxrwx 1 root root       43 Sep 20 16:17 dtb-6.12.43+deb13-arm64 -> ../usr/lib/linux-image-6.12.43+deb13-arm64/
lrwxrwxrwx 1 root root       42 Sep 20 16:18 dtb-6.16.3+deb13-arm64 -> ../usr/lib/linux-image-6.16.3+deb13-arm64/
drwxr-xr-x 3 root root     4096 Sep 20 15:13 efi
drwxr-xr-x 5 root root     4096 Sep 20 16:26 grub
lrwxrwxrwx 1 root root       29 Sep 15 21:30 initrd.img -> initrd.img-6.16.3+deb13-arm64
-rw------- 1 root root 42521317 Sep 20 16:26 initrd.img-6.12.43+deb13-arm64
-rw------- 1 root root 43760872 Sep 20 16:25 initrd.img-6.16.3+deb13-arm64
lrwxrwxrwx 1 root root       30 Sep 15 20:38 initrd.img.old -> initrd.img-6.12.43+deb13-arm64
-rw-r--r-- 1 root root       83 Aug 27 04:10 System.map-6.12.43+deb13-arm64
-rw-r--r-- 1 root root       92 Sep  6 12:48 System.map-6.16.3+deb13-arm64
lrwxrwxrwx 1 root root       26 Sep 15 21:30 vmlinuz -> vmlinuz-6.16.3+deb13-arm64
-rw-r--r-- 1 root root 37449664 Aug 27 04:10 vmlinuz-6.12.43+deb13-arm64
-rw-r--r-- 1 root root 41507328 Sep  6 12:48 vmlinuz-6.16.3+deb13-arm64
lrwxrwxrwx 1 root root       27 Sep 15 20:38 vmlinuz.old -> vmlinuz-6.12.43+deb13-arm64

Note: The relative pathways of the dtb links above assume that the /boot directory is part of the main OS partition, not on its own boot partition. Otherwise you'd need to copy those directories to /boot/ as Armbian does.

 

 

For The Current Partition's OS Entries (each devicetree will be specific to the respective kernel)

1. Open the file with a text/source editor (using sudo):

/etc/grub.d/10_linux

 

2. Find every line that looks something like this (currently on my system, there is only one, and it's line 189)

linux	${rel_dirname}/${basename} root=${linux_root_device_thisversion} ro ${args}

 

3. Just above it, add your own system's version of this line:

devicetree ${rel_dirname}/dtb-${version}/[VENDOR SUB-DIRECTORY]/[SBC PRODUCT].dtb

 

Specific Example: OrangePI-5-Plus

devicetree ${rel_dirname}/dtb-${version}/rockchip/rk3588-orangepi-5-plus.dtb

 

Specific Example from the resulting grub.cfg, of the current trixie-backport kernel, again on the OrangePI-5-Plus:

devicetree /boot/dtb-6.16.3+deb13-arm64/rockchip/rk3588-orangepi-5-plus.dtb

 

 

For Other Partitions' OS Entries, via os-prober (I'm unfamiliar with the variables in this so each devicetree will be the same generic path, regardless of kernel)

1. Open the file with a text/source editor (using sudo):

 /etc/grub.d/30_os-prober

 

2. Find every line that looks something like this (currently on my system, there are two, lines 277 and 297)

linux ${LKERNEL} ${LPARAMS}

 

3. Just above it, add your own system's version of this line:

devicetree /boot/dtb/[VENDOR SUB-DIRECTORY]/[SBC PRODUCT].dtb

 

Specific Example: OrangePI-5-Plus

devicetree /boot/dtb/rockchip/rk3588-orangepi-5-plus.dtb

 

 

Then run update-grub, and take a look at the resulting /boot/grub/grub.cfg

 

 

 

Edited 10 hours ago by The Tall Man