diff --git a/nix/t1/mill-modules.nix b/nix/t1/mill-modules.nix
index 26a720d83..5eaa5d1fa 100644
--- a/nix/t1/mill-modules.nix
+++ b/nix/t1/mill-modules.nix
@@ -153,11 +153,17 @@ let
       mv out/t1package/assembly.dest/out.jar $t1package/share/java/t1package.jar
       mv out/t1package/chiselPluginJar.dest/out.jar $t1package/share/java/chiselPluginJar.jar
 
-      mkdir -p $omreader/bin $elaborator/bin
+      mkdir -p $elaborator/bin
       makeWrapper ${jdk21}/bin/java $elaborator/bin/elaborator \
-        --add-flags "--enable-preview -Djava.library.path=${circt-full}/lib -cp $out/share/java/elaborator.jar"
+        --add-flags "--enable-preview -Djava.library.path=${circt-full}/lib" \
+        --add-flags "-cp $out/share/java/elaborator.jar"
+
+      mkdir -p $omreader/bin
       makeWrapper ${jdk21}/bin/java "$omreader"/bin/omreader \
-        --add-flags "--enable-preview --enable-native-access=ALL-UNNAMED -Djava.library.path=${circt-full}/lib -jar $out/share/java/omreader.jar"
+        --add-flags "--enable-preview" \
+        --add-flags "--enable-native-access=ALL-UNNAMED" \
+        --add-flags "-Djava.library.path=${circt-full}/lib" \
+        --add-flags "-cp $out/share/java/omreader.jar"
     '';
   };
 in
diff --git a/nix/t1/t1.nix b/nix/t1/t1.nix
index b32849ab6..ff9bdb446 100644
--- a/nix/t1/t1.nix
+++ b/nix/t1/t1.nix
@@ -54,13 +54,14 @@ lib.mapAttrs
 
         omGet = args: lib.toLower (lib.fileContents (runCommand "get-${args}" { } ''
           ${t1Scope.omreader-unwrapped}/bin/omreader \
+            ${lib.replaceStrings ["elaborator"] ["omreader"] generator.fullClassName} \
             ${args} \
             --mlirbc-file ${innerMostScope.lowered-mlirbc}/${innerMostScope.lowered-mlirbc.name} \
             > $out
         ''));
         rtlDesignMetadata = with innerMostScope; rec {
           march = omGet "march";
-          extensions = builtins.fromJSON (omGet "extensionsJson");
+          extensions = lib.strings.split "_" (omGet "extensions");
           vlen = omGet "vlen";
           dlen = omGet "dlen";
           xlen = if (lib.hasPrefix "rv32" march) then 32 else 64;