diff --git a/pkgs/build-support/vm/default.nix b/pkgs/build-support/vm/default.nix
index 84222eca98bf..e466ff7ecce8 100644
--- a/pkgs/build-support/vm/default.nix
+++ b/pkgs/build-support/vm/default.nix
@@ -510,8 +510,7 @@ rec {
      tarball must contain an RPM specfile. */
 
   buildRPM = attrs: runInLinuxImage (stdenv.mkDerivation ({
-    prePhases = [ pkgs.prepareImagePhase pkgs.sysInfoPhase ];
-    dontUnpack = true;
+    prePhases = [ "prepareImagePhase" "sysInfoPhase" ];
     dontConfigure = true;
 
     outDir = "rpms/${attrs.diskImage.name}";
@@ -536,9 +535,7 @@ rec {
     buildPhase = ''
       eval "$preBuild"
 
-      # Hacky: RPM looks for <basename>.spec inside the tarball, so
-      # strip off the hash.
-      srcName="$(stripHash "$src")"
+      srcName="$(rpmspec --srpm -q --qf '%{source}' *.spec)"
       cp "$src" "$srcName" # `ln' doesn't work always work: RPM requires that the file is owned by root
 
       export HOME=/tmp/home
diff --git a/pkgs/build-support/vm/test.nix b/pkgs/build-support/vm/test.nix
index 384c92088083..ae6a10dea3b9 100644
--- a/pkgs/build-support/vm/test.nix
+++ b/pkgs/build-support/vm/test.nix
@@ -9,20 +9,23 @@ with vmTools;
 
   buildHelloInVM = runInLinuxVM hello;
 
-  buildPanInVM = runInLinuxVM pan;
+  buildPcmanrmInVM = runInLinuxVM (pcmanfm.overrideAttrs (old: {
+    # goes out-of-memory with many cores
+    enableParallelBuilding = false;
+  }));
 
-
-  testRPMImage = makeImageTestScript diskImages.fedora16x86_64;
+  testRPMImage = makeImageTestScript diskImages.fedora27x86_64;
 
 
   buildPatchelfRPM = buildRPM {
     name = "patchelf-rpm";
     src = patchelf.src;
-    diskImage = diskImages.fedora16x86_64;
+    diskImage = diskImages.fedora27x86_64;
+    diskImageFormat = "qcow2";
   };
 
 
-  testUbuntuImage = makeImageTestScript diskImages.ubuntu810i386;
+  testUbuntuImage = makeImageTestScript diskImages.ubuntu1804i386;
 
 
   buildInDebian = runInLinuxImage (stdenv.mkDerivation {