How to switch arch linux to lts kernel?

Okay, after joe pointed me the right direction in comments, this is how I did it:

1. basicly just install pacman -S linux-lts

2. (optional) check if kernel, ramdisk and fallback are available in ls -lsha /boot

3. remove the standard kernel pacman -R linux

4. update the grub config grub-mkconfig -o /boot/grub/grub.cfg

5. reboot

Note, for syslinux you'll need to edit the syslinux config file in /boot/syslinux/syslinux.cfg accordingly, just point everything to the -lts kernel.

The answer from Afri works well for GRUB, but I’m using UEFI directly, which is more lightweight and makes full use of the UEFI motherboard.

1. Install linux-lts
2. (optional) Check if LTS version of kernel, ramdisk and fallback are available in /boot folder.

3. Generate the EFI entry, the same way as you generated the regular Linux one, but replacing ramdisk and loader with the LTS ones. For example:

   efibootmgr --disk /dev/sdX --part Y --create --label "Arch Linux LTS" --loader /vmlinuz-linux-lts --unicode 'root=PARTUUID=XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX rw initrd=\initramfs-linux-lts.img' --verbose
   

   Note the --loader value and initrd value. These files should be in the /boot folder.

4. Reboot. You may want to adjust the boot order in motherboad before booting into the operating system, for example by pressing F12 (depending on your motherboard). I actually use Hyper-V, which allows boot order configuration in "Hyper-V Manager".

5. (optional) After successfully booting into the LTS kernel (verify it with uname -r), remove the standard kernel with pacman -R linux.

1. Install linux-lts (or any other kernel):

   pacman -S linux-lts
   

2. Update your boot loader entry:

   $ sudo vim /boot/loader/entries/arch.conf 
   

   and change:

   linux   /vmlinuz-linux
   initrd  /initramfs-linux.img
   ↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓
   linux   /vmlinuz-linux-lts
   initrd  /initramfs-linux-lts.img
   

3. Reboot and confirm with uname -r