diff --git a/boot/boot-stage-1.nix b/boot/boot-stage-1.nix
index 49c53e1ed72..7417ab5b2cf 100644
--- a/boot/boot-stage-1.nix
+++ b/boot/boot-stage-1.nix
@@ -38,7 +38,7 @@ let
 
 in
 
-assert autoDetectRootDevice -> mountPoints != [];
+assert !autoDetectRootDevice -> mountPoints != [];
 
 substituteAll {
   src = ./boot-stage-1-init.sh;