Die doppelte Zeile habe ich entfernt.
sudo apt-get install os-prober
Paketlisten werden gelesen… Fertig
Abhängigkeitsbaum wird aufgebaut… Fertig
Statusinformationen werden eingelesen… Fertig
os-prober ist schon die neueste Version (1.84ubuntu1).
Auflösen von Abhängigkeiten… Fertig
0 aktualisiert, 0 neu installiert, 0 zu entfernen und 0 nicht aktualisiert.
os-prober war bei K 24.04 und ist bei K 26.04 installiert.
sudo update-grub
Sourcing file `/etc/default/grub'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-7.0.0-14-generic
Found initrd image: /boot/initrd.img-7.0.0-14-generic
Found linux image: /boot/vmlinuz-6.8.0-110-generic
Found initrd image: /boot/initrd.img-6.8.0-110-generic
Found memtest86+ 64bit EFI image: /boot/mt86+x64
Found memtest86+ 32bit EFI image: /boot/mt86+ia32
Found memtest86+ 64bit image: /boot/mt86+x64
Found memtest86+ 32bit image: /boot/mt86+ia32
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
Found Windows Boot Manager on /dev/sda1@/EFI/Microsoft/Boot/bootmgfw.efi
Found Arch Linux on /dev/sda8
Adding boot menu entry for UEFI Firmware Settings ...
done
Das Menu wird leider nicht angezeigt.
#GRUB_DEFAULT=saved
#GRUB_SAVEDEFAULT=true
#GRUB_DEFAULT=0
#GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=2
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX="locale=en"
GRUB_TIMEOUT_STYLE=menu
GRUB_DISABLE_OS_PROBER=false
GRUB_GFXMODE=1400x1050
GRUB_GFXPAYLOAD_Linux=keep
Was muss ich ändern?
https://gitlab.com/scripts94/kubuntu-26.04-lts-important-things-to-do-after-an-installation
4.b) Change GRUB to show the boot menu with all installed systems for 5 seconds in multi-boot setups
(= Kubuntu and another Linux or/and Windows are installed - and make sure to definitely disable Windows fast startup if you intend to access the "C:" drive from Linux).
sudo cp /etc/default/grub /etc/default/grub.orig
(this makes a backup of your /etc/default/grub file first)
sudo sed -i 's/GRUB_TIMEOUT_STYLE=hidden/GRUB_TIMEOUT_STYLE=menu/' /etc/default/grub
(this makes GRUB show the boot menu)
sudo sed -i 's/GRUB_TIMEOUT=0/GRUB_TIMEOUT=5/' /etc/default/grub
(this writes the timeout value to your system)
sudo sed -i 's/#GRUB_DISABLE_OS_PROBER=false/GRUB_DISABLE_OS_PROBER=false/' /etc/default/grub
(this makes other systems visible in the boot menu)
sudo update-grub
(this updates your GRUB boot loader with the new values)
The change will be visible during the reboot after step 6. (7.)