diff --git a/nixos/modules/installer/cd-dvd/sd-image.nix b/nixos/modules/installer/cd-dvd/sd-image.nix
index c8c5a46dfb8..b811ae07eb0 100644
--- a/nixos/modules/installer/cd-dvd/sd-image.nix
+++ b/nixos/modules/installer/cd-dvd/sd-image.nix
@@ -223,7 +223,7 @@ in
         # Figure out device names for the boot device and root filesystem.
         rootPart=$(${pkgs.util-linux}/bin/findmnt -n -o SOURCE /)
         bootDevice=$(lsblk -npo PKNAME $rootPart)
-        partNum=$(lsblk -npo MAJ:MIN $rootPart | awk -F: '{print $2}')
+        partNum=$(lsblk -npo MAJ:MIN $rootPart | ${pkgs.gawk}/bin/awk -F: '{print $2}')
 
         # Resize the root partition and the filesystem to fit the disk
         echo ",+," | sfdisk -N$partNum --no-reread $bootDevice