diff --git a/amaranth/lib/io.py b/amaranth/lib/io.py
index c2bc59a10..c7a4bc2f0 100644
--- a/amaranth/lib/io.py
+++ b/amaranth/lib/io.py
@@ -518,6 +518,11 @@ class Buffer(wiring.Component):
     ----------
     signature : :class:`Buffer.Signature`
         :py:`Signature(direction, len(port)).flip()`.
+
+    Platform overrides
+    ------------------
+    Define the :py:`get_io_buffer()` platform method to override the implementation of
+    :class:`Buffer`, e.g. to instantiate library cells directly.
     """
     class Signature(wiring.Signature):
         """Signature of a combinational I/O buffer.
@@ -587,6 +592,8 @@ def direction(self):
     def elaborate(self, platform):
         if hasattr(platform, "get_io_buffer"):
             return platform.get_io_buffer(self)
+        elif not isinstance(self._port, (SingleEndedPort, DifferentialPort, SimulationPort)):
+            raise TypeError("Cannot elaborate generic 'Buffer' with port {self._port!r}") # :nocov:
 
         m = Module()
 
@@ -632,8 +639,6 @@ def elaborate(self, platform):
             if self.direction in (Direction.Output, Direction.Bidir):
                 m.d.comb += self._port.o.eq(o_inv)
                 m.d.comb += self._port.oe.eq(self.oe.replicate(len(self._port)))
-        else:
-            raise TypeError("Cannot elaborate generic 'Buffer' with port {self._port!r}") # :nocov:
 
         return m
 
@@ -690,6 +695,11 @@ class FFBuffer(wiring.Component):
     ----------
     signature : :class:`FFBuffer.Signature`
         :py:`Signature(direction, len(port)).flip()`.
+
+    Platform overrides
+    ------------------
+    Define the :py:`get_io_buffer()` platform method to override the implementation of
+    :class:`FFBuffer`, e.g. to instantiate library cells directly.
     """
     class Signature(wiring.Signature):
         """Signature of a registered I/O buffer.
@@ -898,6 +908,11 @@ class DDRBuffer(wiring.Component):
     ----------
     signature : :class:`DDRBuffer.Signature`
         :py:`Signature(direction, len(port)).flip()`.
+
+    Platform overrides
+    ------------------
+    Define the :py:`get_io_buffer()` platform method to override the implementation of
+    :class:`DDRBuffer`, e.g. to instantiate library cells directly.
     """
     class Signature(wiring.Signature):
         """Signature of a double data rate I/O buffer.