User talk:Hatul
In each menu entry in your grub.cfg
you will see something like
echo 'Loading initial ramdisk ...' initrd /boot/initramfs-linux.img
Add in the microcode image like this for each entry
echo 'Loading initial ramdisk ...' initrd /intel-ucode.img /boot/initramfs-linux.img
Are you sure not need /boot/intel-ucode.img ?
According to the wiki
"Remember that the path to /intel-ucode.img is relative to the boot partition, just as that of initramfs. This means that if you have a dedicated /boot partition you should use /intel-ucode.img; else use /boot/intel-ucode.img. There is an open Bug Report (FS#42354) for proper support of microde updates in grub-mkconfig."