I never would have thought that the most time-consuming step would be screwing in the screws after installing the replacement motherboard, which took a full two hours. It’s puzzling why the designers placed the screw holes so close to the strong magnets.

After replacing the motherboard, since the NVRAM no longer has the boot options stored, grub needs to be redeployed.

Boot using a USB live CD, and mount the original hard drive partitions to /mnt and /mnt/boot.

Enter the chroot environment with arch-chroot /mnt and redeploy grub:

grub-install --target=x86_64-efi --efi-directory=/boot --bootloader-id=grub
grub-mkconfig -o /boot/grub/grub.cfg
exit

After unmounting and rebooting the computer, I was finally able to use the 12th Gen Intel CPU, just in time before the release of the 13th Gen CPU.