diff --git a/tests/driver-linux.nix b/tests/driver-linux.nix
index b428204..2a1023c 100644
--- a/tests/driver-linux.nix
+++ b/tests/driver-linux.nix
@@ -41,9 +41,9 @@ let
 
       baseSetup = with testPkgs; ''
         file link -s core ${depot.base-linux}/bin/core
-        file link -s timer ${depot.base-linux}/bin/timer
+        file link -s timer ${genode.base-linux}/bin/linux_timer_drv
         file link -s ld.lib.so ${depot.base-linux}/lib/ld.lib.so
-        file link -s init ${depot.init}/bin/init
+        file link -s init ${genode.os}/bin/init
         file link -s config ${./driver-config.xml}
         file link -s test.config $env(testConfig)
       '';
diff --git a/upstream/default.nix b/upstream/default.nix
index c979c16..4d0f572 100644
--- a/upstream/default.nix
+++ b/upstream/default.nix
@@ -53,8 +53,10 @@ let
         LIBCXX = llvmPackages.libcxx;
         LIBCXXABI = llvmPackages.libcxxabi;
         LIBUNWIND = llvmPackages.libunwind;
-        LIBUNWIND_BAREMETAL = llvmPackages.libunwind.override { isBaremetal = true; };
+        LIBUNWIND_BAREMETAL =
+          llvmPackages.libunwind.override { isBaremetal = true; };
         LINUX_HEADERS = buildPackages.glibc.dev;
+        OLEVEL = "-O2";
         TUP_ARCH = tupArch;
         VERSION = version;
       };
@@ -92,7 +94,8 @@ let
 
       installPhase = ''
         # Populate the "dev" headers
-        for DIR in repos/$repo/include; do
+        if [ -d "repos/$repo/include" ]; then
+          for DIR in repos/$repo/include; do
             for SPEC in $specs; do
               if [ -d $DIR/spec/$SPEC ]; then
                 cp -r $DIR/spec/$SPEC/* $dev/include
@@ -101,7 +104,8 @@ let
             done
             rm -rf $DIR/spec
             cp -r $DIR $dev/
-        done
+          done
+        fi
 
         touch $dev/.genode
         for pc in $dev/lib/pkgconfig/*.pc; do