diff --git a/common/cmdlib.cc b/common/cmdlib.cc
index acf6b921..d4817e3e 100644
--- a/common/cmdlib.cc
+++ b/common/cmdlib.cc
@@ -744,7 +744,7 @@ DefaultExtension(char *path, const char *extension)
     /* (extension should include the .)              */
     src = path + strlen(path) - 1;
 
-    while (*src != PATHSEPERATOR && src != path) {
+    while (*src != PATHSEPERATOR && *src != '\\' && src != path) {
         if (*src == '.')
             return;             /* it has an extension */
         src--;
@@ -784,7 +784,7 @@ StripExtension(char *path)
     length = strlen(path) - 1;
     while (length > 0 && path[length] != '.') {
         length--;
-        if (path[length] == '/')
+        if (path[length] == '/' || path[length] == '\\')
             return;             /* no extension */
     }
     if (length)
@@ -799,7 +799,7 @@ StrippedExtension(const std::string& path) {
     length = static_cast<int>(path.size()) - 1;
     while (length > 0 && path[length] != '.') {
         length--;
-        if (path[length] == '/')
+        if (path[length] == '/' || path[length] == '\\')
             return path;             /* no extension */
     }
     if (length)
@@ -842,9 +842,10 @@ ExtractFileBase(char *path, char *dest)
     src = path + strlen(path) - 1;
 
     /* back up until a \ or the start */
-    while (src != path && *(src - 1) != PATHSEPERATOR)
+    while (src != path && *(src - 1) != PATHSEPERATOR
+                       && *(src - 1) != '\\') {
         src--;
-
+    }
     while (*src && *src != '.') {
         *dest++ = *src++;
     }
diff --git a/include/qbsp/writebsp.hh b/include/qbsp/writebsp.hh
index 90ee1474..073d53e0 100644
--- a/include/qbsp/writebsp.hh
+++ b/include/qbsp/writebsp.hh
@@ -27,5 +27,6 @@ int ExportMapTexinfo(int texinfonum);
 
 void BeginBSPFile(void);
 void FinishBSPFile(void);
+void UpdateBSPFileEntitiesLump();
 
 #endif
diff --git a/qbsp/qbsp.cc b/qbsp/qbsp.cc
index 70557cc1..54969893 100644
--- a/qbsp/qbsp.cc
+++ b/qbsp/qbsp.cc
@@ -302,9 +302,8 @@ UpdateEntLump(void)
             FixRotateOrigin(entity);
     }
 
-    //LoadBSPFile(); // FIXME: fix -onlyents
-    WriteEntitiesToString();    
-    //WriteBSPFile(); // FIXME: fix -onlyents
+    WriteEntitiesToString();
+    UpdateBSPFileEntitiesLump();
 
     if (!options.fAllverbose)
         options.fVerbose = false;
diff --git a/qbsp/writebsp.cc b/qbsp/writebsp.cc
index 1733f383..c0d87341 100644
--- a/qbsp/writebsp.cc
+++ b/qbsp/writebsp.cc
@@ -469,3 +469,29 @@ FinishBSPFile(void)
 
     options.fVerbose = options.fAllverbose;
 }
+
+/*
+==================
+UpdateBSPFileEntitiesLump
+==================
+*/
+void
+UpdateBSPFileEntitiesLump()
+{
+    bspdata_t bspdata;
+    StripExtension(options.szBSPName);
+    DefaultExtension(options.szBSPName, ".bsp");
+
+    // load the .bsp
+    LoadBSPFile(options.szBSPName, &bspdata);
+    ConvertBSPFormat(&bspdata, &bspver_generic);
+
+    // replace the existing entities lump with map.exported_entities
+    CopyString(map.exported_entities, true, &bspdata.data.mbsp.entdatasize, (void**)&bspdata.data.mbsp.dentdata);
+
+    // write the .bsp back to disk
+    ConvertBSPFormat(&bspdata, bspdata.loadversion);
+    WriteBSPFile(options.szBSPName, &bspdata);
+
+    logprint("Wrote %s\n", options.szBSPName);
+}