diff --git a/ghc/driver/ghc.lprl b/ghc/driver/ghc.lprl
index 6b04bb0b43e85150bdd00b528bed859490eb1197..fedb756a17405e1fef5b8052cdbf5ac7e72ff404 100644
--- a/ghc/driver/ghc.lprl
+++ b/ghc/driver/ghc.lprl
@@ -908,7 +908,9 @@ sub setupBuildFlags {
       $BuildTag = '_t';
 
   } elsif ( $UNREGing eq 'u' ) {
-      $BuildTag = '_u';
+      if ($GhcWithRegisterised eq 'YES') {
+	 $BuildTag = '_u';
+      }
   }
 \end{code}
 
@@ -939,8 +941,6 @@ Decide what the consistency-checking options are in force for this run:
 
        if ($CompilingPrelude) {
          $HiSuffix_prelude = "$HiSuffix" if $CompilingPrelude;
-       } elsif ($BuildTag eq '_u' && $GhcWithRegisterised eq 'NO') {
-	 $HiSuffix_prelude = 'hi';
        } else {
          local($Tag) = "${BuildTag}";