diff --git a/src/KKdLib/f2/header.cpp b/src/KKdLib/f2/header.cpp
index b6f36620..a25dc00a 100644
--- a/src/KKdLib/f2/header.cpp
+++ b/src/KKdLib/f2/header.cpp
@@ -174,7 +174,7 @@ bool f2_header::validate_crc(int32_t not_ignore_crc) {
 }
 
 void f2_header::write(stream& s) {
-    if (s.check_null())
+    if (s.check_null() && !reinterpret_cast<struct memory_stream*>(&s))
         return;
 
     s.write(this, get_length());
diff --git a/src/KKdLib/f2/struct.cpp b/src/KKdLib/f2/struct.cpp
index ad7583b8..434c545c 100644
--- a/src/KKdLib/f2/struct.cpp
+++ b/src/KKdLib/f2/struct.cpp
@@ -120,7 +120,7 @@ void f2_struct::write(void** data, size_t* size, bool use_depth, bool shift_x) {
 }
 
 void f2_struct::write(stream& s, bool use_depth, bool shift_x) {
-    if (s.check_null())
+    if (s.check_null() && !reinterpret_cast<memory_stream*>(&s))
         return;
 
     f2_struct_get_length(this, shift_x);
diff --git a/src/KKdLib/obj.cpp b/src/KKdLib/obj.cpp
index 4ce72921..9cf9b1bc 100644
--- a/src/KKdLib/obj.cpp
+++ b/src/KKdLib/obj.cpp
@@ -4270,9 +4270,8 @@ static void obj_set_modern_write_inner(obj_set* set, stream& s) {
         s_omdl.big_endian = big_endian;
 
         if (obj->skin) {
-            st.sub_structs.push_back({});
-            omdl = &st.sub_structs.end()[-2];
-            f2_struct* oskn = &st.sub_structs.back();
+            omdl->sub_structs.push_back({});
+            f2_struct* oskn = &omdl->sub_structs.back();
 
             memory_stream s_oskn;
             s_oskn.open();
@@ -4285,7 +4284,7 @@ static void obj_set_modern_write_inner(obj_set* set, stream& s) {
             s_oskn.close();
 
             new (&oskn->header) f2_header('OSKN');
-            oskn->header.attrib.set_big_endian(big_endian);
+            omdl->header.attrib.set_big_endian(big_endian);
         }
 
         obj_modern_write_model(obj, s_omdl, 0, is_x, omdl);