diff --git a/deployment/flake-part.nix b/deployment/flake-part.nix
index 7f2af2fb..54ac5621 100644
--- a/deployment/flake-part.nix
+++ b/deployment/flake-part.nix
@@ -2,7 +2,6 @@
 
 let
   allVmIds = builtins.genList (x: 100 + x) 156; # 100 -- 255
-  makeInstallerIso = import ../infra/makeInstallerIso.nix;
 
 in
 {
@@ -26,24 +25,6 @@ in
       }) allVmIds
     );
 
-  flake.isoInstallers.provisioning =
-    let
-      inherit (builtins) mapAttrs;
-    in
-    mapAttrs (
-      vmname: nixosConfiguration:
-      makeInstallerIso {
-        inherit (inputs) nixpkgs;
-        inherit nixosConfiguration;
-        hostKeys = {
-          ed25519 = {
-            private = ./hostKeys/${vmname}/ssh_host_ed25519_key;
-            public = ./hostKeys/${vmname}/ssh_host_ed25519_key.pub;
-          };
-        };
-      }
-    ) self.nixosConfigurations.provisioning;
-
   nixops4Deployments.feditest =
     { providers, ... }:
 
diff --git a/deployment/proxmox/provision.sh b/deployment/proxmox/provision.sh
index 605ef4c4..0682d4f7 100755
--- a/deployment/proxmox/provision.sh
+++ b/deployment/proxmox/provision.sh
@@ -177,7 +177,19 @@ build_iso () {
   printf 'Building ISO for VM %d...\n' "$1"
 
   nix build \
-    ".#isoInstallers.provisioning.fedi$1" \
+    --impure --expr "
+      let flake = builtins.getFlake (builtins.toString ./.); in
+      flake.lib.makeInstallerIso {
+        nixosConfiguration = flake.nixosConfigurations.provisioning.fedi$1;
+        nixpkgs = flake.inputs.nixpkgs;
+        hostKeys = {
+          ed25519 = {
+            private = ./deployment/hostKeys/fedi$1/ssh_host_ed25519_key;
+            public = ./deployment/hostKeys/fedi$1/ssh_host_ed25519_key.pub;
+          };
+        };
+      }
+    " \
     --log-format raw --quiet \
     --out-link "$tmpdir/installer-fedi$1"