diff --git a/docs/guide-passthrough.md b/docs/guide-passthrough.md
index a2ddb34..2678937 100644
--- a/docs/guide-passthrough.md
+++ b/docs/guide-passthrough.md
@@ -35,7 +35,7 @@ iommu=pt amd_iommu=on vfio-pci.ids=1002:66af,1002:ab20
 iommu=pt intel_iommu=on vfio-pci.ids=1002:66af,1002:ab20
 ```
 
-To do this permanently, you can add it to your bootloader. If you're using GRUB, for example, edit `/etc/default/grub` and add the previous lines to the `GRUB_CMDLINE_LINUX_DEFAULT` section.
+To do this permanently, you can add it to your bootloader. If you're using GRUB, for example, edit `/etc/default/grub` and add the previous lines to the `GRUB_CMDLINE_LINUX_DEFAULT` section, then run `sudo update-grub` and reboot.
 
 ## Attach card to QEMU
 You will need to attach the cards using the BDF IDs for the audio and video controller. The following example shows the config for a card with two devices. The romfile parameter is optional.