Adding boot menu entry for UEFI Firmware Settings ...
done
Setting up linux-libc-dev:amd64 (6.8.2-1) ...
+```
+
+```shell
+$ sudo vim /boot/grub/grub.cfg
+# find menuentry `'Ubuntu, with Linux 6.8.2-rt11'`
+
+```
+
+```shell
+$ sudo vim /etc/default/grub
+
+# change `GRUB_DEFAULT` to the found entry
+# GRUB_DEFAULT='Advanced options for Ubuntu>Ubuntu, with Linux 6.8.2-rt11'
+
+```
+
+
+```shell
+$ uname -a
+Linux thy-Z370-HD3 6.8.2-rt11 #1 SMP PREEMPT_RT Tue Oct 28 16:56:00 KST 2025 x86_64 x86_64 x86_64 GNU/Linux
+
+
```
\ No newline at end of file