diff --git a/pkgs/development/compilers/factor-lang/factor99.nix b/pkgs/development/compilers/factor-lang/factor99.nix
index 5d60f1d51568..85ff98a28ba1 100644
--- a/pkgs/development/compilers/factor-lang/factor99.nix
+++ b/pkgs/development/compilers/factor-lang/factor99.nix
@@ -150,6 +150,11 @@ stdenv.mkDerivation {
       done)> $out/lib/factor/ld.so.cache
 
     make -j$NIX_BUILD_CORES linux-x86-64
+    printf "First build from upstream boot image\n" >&2
+    ./build.sh bootstrap
+    printf "Rebuild boot image\n" >&2
+    ./factor -script -e='"unix-x86.64" USING: system bootstrap.image memory ; make-image save 0 exit'
+    printf "Second build from local boot image\n" >&2
     ./build.sh bootstrap
     runHook postBuild
   '';
@@ -214,5 +219,6 @@ stdenv.mkDerivation {
     license = licenses.bsd2;
     maintainers = with maintainers; [ vrthra spacefrogg ];
     platforms = lib.intersectLists platforms.x86_64 platforms.linux;
+    mainProgram = "factor";
   };
 }