diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index 5f6ac01f3..4534481e7 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -21,6 +21,10 @@ TARGET_LINK_LIBRARIES(dfvdig dfhack)
 ADD_EXECUTABLE(dfcleanmap cleanmap.cpp)
 TARGET_LINK_LIBRARIES(dfcleanmap dfhack)
 
+# unstuck - make DF run if something goes wrong with the 'normal' memory access method
+ADD_EXECUTABLE(dfunstuck unstuck.cpp)
+TARGET_LINK_LIBRARIES(dfunstuck dfhack)
+
 IF(UNIX)
 # incrementalsearch - a bit like cheat engine, only DF-specific, very basic
 # and Linux-only
diff --git a/tools/vdig.cpp b/tools/vdig.cpp
index 3b5c455b7..93eceefce 100644
--- a/tools/vdig.cpp
+++ b/tools/vdig.cpp
@@ -105,20 +105,24 @@ class Block
     {
         return raw.designation[p.x][p.y];
     }
-    DFHack::t_designation setDesignationAt(Point p, DFHack::t_designation des)
+    bool setDesignationAt(Point p, DFHack::t_designation des)
     {
+        if(!valid) return false;
         dirty = true;
         //printf("setting block %d/%d/%d , %d %d\n",x,y,z, p.x, p.y);
         raw.designation[p.x][p.y] = des;
+        return true;
     }
     bool WriteDesignations ()
     {
+        if(!valid) return false;
         if(dirty)
         {
             //printf("writing %d/%d/%d\n",x,y,z);
             m->WriteDesignations(x,y,z, &raw.designation);
             m->WriteDirtyBit(x,y,z,true);
         }
+        return true;
     }
     bool valid;
     bool dirty;
@@ -171,6 +175,7 @@ class Layer
         {
             Block * nblo = new Block(Maps,blockcoord.x,blockcoord.y,z);
             blocks[blockcoord] = nblo;
+            return nblo;
         }
     }
     
@@ -234,6 +239,7 @@ class Layer
             p->second->WriteDesignations();
             //cout << stonetypes[p->first].id << " : " << p->second << endl;
         }
+        return true;
     }
     private:
     bool valid;