diff --git a/pkgs/development/libraries/box2d/2.0.1.nix b/pkgs/development/libraries/box2d/2.0.1.nix
index d714be740eb..9aa08caf00f 100644
--- a/pkgs/development/libraries/box2d/2.0.1.nix
+++ b/pkgs/development/libraries/box2d/2.0.1.nix
@@ -27,7 +27,7 @@ rec {
   inherit (sourceInfo) name version;
   inherit buildInputs;
 
-  phaseNames = ["fixIncludes" "setVars" "doMake" "doDeploy"];
+  phaseNames = ["fixIncludes" "setVars" "changeSettings" "doMake" "doDeploy"];
 
   goSrcDir = ''cd Box2D'';
 
@@ -58,6 +58,10 @@ rec {
     ensureDir "$out/share"
     cp -r Examples "$out/share"
   '' ["minInit" "addInputs" "doMake" "defEnsureDir"];
+
+  changeSettings = a.fullDepEntry ''
+    sed -i Source/Common/b2Settings.h -e 's@b2_maxPolygonVertices .*@b2_maxPolygonVertices = 15;@'
+  '' ["minInit" "addInputs" "doUnpack"];
       
   meta = {
     description = "2D physics engine";
diff --git a/pkgs/development/libraries/box2d/default.nix b/pkgs/development/libraries/box2d/default.nix
index d73d24af2ff..9d261191fbb 100644
--- a/pkgs/development/libraries/box2d/default.nix
+++ b/pkgs/development/libraries/box2d/default.nix
@@ -27,8 +27,12 @@ rec {
   inherit (sourceInfo) name version;
   inherit buildInputs;
 
-  phaseNames = ["doCmake" "doMakeInstall"];
+  phaseNames = ["changeSettings" "doCmake" "doMakeInstall"];
 
+  changeSettings = a.fullDepEntry ''
+    sed -i Box2D/Common/b2Settings.h -e 's@b2_maxPolygonVertices .*@b2_maxPolygonVertices 15@'
+  '' ["minInit" "addInputs" "doUnpack"];
+      
   goSrcDir = ''cd Box2D'';
 
   doCmake = a.fullDepEntry ''