diff --git a/nix/t1/conversion/sv-to-vcs-simulator.nix b/nix/t1/conversion/sv-to-vcs-simulator.nix
index 7d9b700d1..2e902f9ed 100644
--- a/nix/t1/conversion/sv-to-vcs-simulator.nix
+++ b/nix/t1/conversion/sv-to-vcs-simulator.nix
@@ -21,6 +21,7 @@ stdenv.mkDerivation rec {
   # require license
   __noChroot = true;
   dontPatchELF = true;
+  enableCover = true;
 
   src = rtl;
 
@@ -30,6 +31,8 @@ stdenv.mkDerivation rec {
     "-timescale=1ns/1ps"
     "-file"
     "filelist.f"
+  ]
+  ++ lib.optionals (enableCover) [
     "-cm"
     "line+cond+fsm+tgl+branch+assert"
     "-cm_dir"
@@ -39,6 +42,8 @@ stdenv.mkDerivation rec {
     "+define+T1_ENABLE_TRACE"
     "-debug_access+pp+dmptf+thread"
     "-kdb=common_elab,hgldd_all"
+    "-assert"
+    "disable_cover"
   ]
   ++ vcsLinkLibs;
 
@@ -69,16 +74,21 @@ stdenv.mkDerivation rec {
     mkdir -p $out/bin $out/lib
     cp $mainProgram $out/lib
     cp -r $mainProgram.daidir $out/lib
-    cp -r ./cm.vdb $out/lib
+    ${lib.optionalString enableCover ''
+      cp -r ./cm.vdb $out/lib 
+    ''}
 
     # We need to carefully handle string escape here, so don't use makeWrapper
     tee $out/bin/$mainProgram <<EOF
     #!${bash}/bin/bash
     export LD_LIBRARY_PATH="$out/lib/$mainProgram.daidir:\$LD_LIBRARY_PATH"
     _argv="\$@"
-    cp -r $out/lib/cm.vdb ./cm.vdb
-    chmod +w -R ./cm.vdb
-    ${vcs-fhs-env}/bin/vcs-fhs-env -c "$out/lib/$mainProgram -cm_dir ./cm.vdb \$_argv"
+
+    ${lib.optionalString enableCover ''
+      cp -r $out/lib/cm.vdb ./cm.vdb
+      chmod +w -R ./cm.vdb
+    ''}
+    ${vcs-fhs-env}/bin/vcs-fhs-env -c "$out/lib/$mainProgram ${lib.optionalString enableCover ''-cm_dir ./cm.vdb''} \$_argv"
     EOF
     chmod +x $out/bin/$mainProgram
 
diff --git a/script/emu/src/Main.scala b/script/emu/src/Main.scala
index 241cf089e..41f9893de 100644
--- a/script/emu/src/Main.scala
+++ b/script/emu/src/Main.scala
@@ -181,7 +181,7 @@ object Main:
       )
 
     val isTrace = finalEmuType.get.contains("-trace")
-    val isCover = isTrace
+    val isCover = true
 
     val finalConfig = tryRestoreFromCache("config", config)
     if finalConfig.isEmpty then