diff --git a/nixos/maintainers/scripts/ec2/amazon-image.nix b/nixos/maintainers/scripts/ec2/amazon-image.nix
index eeae27ede0f..88d95e67544 100644
--- a/nixos/maintainers/scripts/ec2/amazon-image.nix
+++ b/nixos/maintainers/scripts/ec2/amazon-image.nix
@@ -53,6 +53,7 @@ in {
     pkgs = import ../../../.. { inherit (pkgs) system; }; # ensure we use the regular qemu-kvm package
     partitionTableType = if config.ec2.hvm then "legacy" else "none";
     diskSize = cfg.sizeMB;
+    fsType = "ext4";
     configFile = pkgs.writeText "configuration.nix"
       ''
         {
diff --git a/nixos/modules/virtualisation/amazon-image.nix b/nixos/modules/virtualisation/amazon-image.nix
index 6f4f99caa6f..d67790702f1 100644
--- a/nixos/modules/virtualisation/amazon-image.nix
+++ b/nixos/modules/virtualisation/amazon-image.nix
@@ -31,6 +31,7 @@ in
 
     fileSystems."/" = {
       device = "/dev/disk/by-label/nixos";
+      fsType = "ext4";
       autoResize = true;
     };