diff --git a/lib/core/text/flat.nit b/lib/core/text/flat.nit
index 45ad144d4a..9f5659ad68 100644
--- a/lib/core/text/flat.nit
+++ b/lib/core/text/flat.nit
@@ -991,15 +991,10 @@ class FlatBuffer
 	init from(s: Text)
 	do
 		_items = new NativeString(s.bytelen)
-		if s isa FlatText then
-			_items = s._items
-		else
-			for i in substrings do i.as(FlatString)._items.copy_to(_items, i._bytelen, 0, 0)
-		end
+		for i in s.substrings do i._items.copy_to(_items, i._bytelen, first_byte, 0)
 		_bytelen = s.bytelen
 		_length = s.length
 		_capacity = _bytelen
-		written = true
 	end
 
 	# Create a new empty string with a given capacity.
diff --git a/tests/sav/test_flatbuf_from.res b/tests/sav/test_flatbuf_from.res
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/sav/test_flatbuf_from_alt1.res b/tests/sav/test_flatbuf_from_alt1.res
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/sav/test_flatbuf_from_alt2.res b/tests/sav/test_flatbuf_from_alt2.res
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/test_flatbuf_from.nit b/tests/test_flatbuf_from.nit
new file mode 100644
index 0000000000..a91883f601
--- /dev/null
+++ b/tests/test_flatbuf_from.nit
@@ -0,0 +1,25 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+#alt2 intrude import core::text::ropes
+
+var a = "String"
+
+var s: Text = a
+#alt1 s = new FlatBuffer
+#alt1 s.append(a)
+#alt2 var b = a
+#alt2 s = new Concat(a, b)
+
+var buf = new FlatBuffer.from(s)