diff --git a/machines/petra/disko.nix b/machines/petra/disko.nix
index 7880e06..da4c143 100644
--- a/machines/petra/disko.nix
+++ b/machines/petra/disko.nix
@@ -1,7 +1,7 @@
 { ... }:
 let
   hashDisk = disk: "os-${builtins.substring 0 5 (builtins.hashString "sha256" disk)}";
-  os = "/dev/disk/by-id/FIXME";
+  os = "/dev/disk/by-id/ata-TOSHIBA_MQ01ABD100_85N8C2DPT";
 in
 {