diff --git a/etc/default/grub.d/40_kernel_hardening.cfg b/etc/default/grub.d/40_kernel_hardening.cfg
index eaedccb..8285744 100644
--- a/etc/default/grub.d/40_kernel_hardening.cfg
+++ b/etc/default/grub.d/40_kernel_hardening.cfg
@@ -128,7 +128,7 @@ GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX debugfs=off"
 ## Enable CPU manufacturer-specific IOMMU drivers to protect against DMA attacks.
 ##
 GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX amd_iommu=force_isolation"
-GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX intel_iommu"
+GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX intel_iommu=on"
 
 ## Enable and force use of IOMMU translation to protect against DMA attacks.
 ## Strictly force DMA unmap operations to synchronously invalidate IOMMU hardware TLBs.