diff --git a/amaranth/vendor/_altera.py b/amaranth/vendor/_altera.py
index 8d043a9..0b206a5 100644
--- a/amaranth/vendor/_altera.py
+++ b/amaranth/vendor/_altera.py
@@ -475,9 +475,13 @@ class AlteraPlatform(TemplatedPlatform):
         if isinstance(buffer, io.Buffer):
             result = IOBuffer(buffer.direction, buffer.port)
         elif isinstance(buffer, io.FFBuffer):
-            result = FFBuffer(buffer.direction, buffer.port)
+            result = FFBuffer(buffer.direction, buffer.port,
+                              i_domain=buffer.i_domain,
+                              o_domain=buffer.o_domain)
         elif isinstance(buffer, io.DDRBuffer):
-            result = DDRBuffer(buffer.direction, buffer.port)
+            result = DDRBuffer(buffer.direction, buffer.port,
+                               i_domain=buffer.i_domain,
+                               o_domain=buffer.o_domain)
         else:
             raise TypeError(f"Unsupported buffer type {buffer!r}") # :nocov:
         if buffer.direction is not io.Direction.Output:
diff --git a/amaranth/vendor/_gowin.py b/amaranth/vendor/_gowin.py
index 17d7d73..beae85a 100644
--- a/amaranth/vendor/_gowin.py
+++ b/amaranth/vendor/_gowin.py
@@ -543,9 +543,13 @@ class GowinPlatform(TemplatedPlatform):
         if isinstance(buffer, io.Buffer):
             result = IOBuffer(buffer.direction, buffer.port)
         elif isinstance(buffer, io.FFBuffer):
-            result = FFBuffer(buffer.direction, buffer.port)
+            result = FFBuffer(buffer.direction, buffer.port,
+                              i_domain=buffer.i_domain,
+                              o_domain=buffer.o_domain)
         elif isinstance(buffer, io.DDRBuffer):
-            result = DDRBuffer(buffer.direction, buffer.port)
+            result = DDRBuffer(buffer.direction, buffer.port,
+                               i_domain=buffer.i_domain,
+                               o_domain=buffer.o_domain)
         else:
             raise TypeError(f"Unsupported buffer type {buffer!r}") # :nocov:
         if buffer.direction is not io.Direction.Output:
diff --git a/amaranth/vendor/_lattice.py b/amaranth/vendor/_lattice.py
index 4e6125f..94d03d7 100644
--- a/amaranth/vendor/_lattice.py
+++ b/amaranth/vendor/_lattice.py
@@ -998,18 +998,28 @@ class LatticePlatform(TemplatedPlatform):
             result = IOBuffer(buffer.direction, buffer.port)
         elif isinstance(buffer, io.FFBuffer):
             if self.family in ("ecp5", "machxo2"):
-                result = FFBufferECP5(buffer.direction, buffer.port)
+                result = FFBufferECP5(buffer.direction, buffer.port,
+                                      i_domain=buffer.i_domain,
+                                      o_domain=buffer.o_domain)
             elif self.family == "nexus":
-                result = FFBufferNexus(buffer.direction, buffer.port)
+                result = FFBufferNexus(buffer.direction, buffer.port,
+                                       i_domain=buffer.i_domain,
+                                       o_domain=buffer.o_domain)
             else:
                 raise NotImplementedError # :nocov:
         elif isinstance(buffer, io.DDRBuffer):
             if self.family == "ecp5":
-                result = DDRBufferECP5(buffer.direction, buffer.port)
+                result = DDRBufferECP5(buffer.direction, buffer.port,
+                                       i_domain=buffer.i_domain,
+                                       o_domain=buffer.o_domain)
             elif self.family == "machxo2":
-                result = DDRBufferMachXO2(buffer.direction, buffer.port)
+                result = DDRBufferMachXO2(buffer.direction, buffer.port,
+                                          i_domain=buffer.i_domain,
+                                          o_domain=buffer.o_domain)
             elif self.family == "nexus":
-                result = DDRBufferNexus(buffer.direction, buffer.port)
+                result = DDRBufferNexus(buffer.direction, buffer.port,
+                                        i_domain=buffer.i_domain,
+                                        o_domain=buffer.o_domain)
             else:
                 raise NotImplementedError # :nocov:
         else:
diff --git a/amaranth/vendor/_xilinx.py b/amaranth/vendor/_xilinx.py
index f27f013..e762839 100644
--- a/amaranth/vendor/_xilinx.py
+++ b/amaranth/vendor/_xilinx.py
@@ -1168,16 +1168,26 @@ class XilinxPlatform(TemplatedPlatform):
         if isinstance(buffer, io.Buffer):
             result = IOBuffer(buffer.direction, buffer.port)
         elif isinstance(buffer, io.FFBuffer):
-            result = FFBuffer(buffer.direction, buffer.port)
+            result = FFBuffer(buffer.direction, buffer.port,
+                              i_domain=buffer.i_domain,
+                              o_domain=buffer.o_domain)
         elif isinstance(buffer, io.DDRBuffer):
             if self.family in ("virtex2", "virtex2p", "spartan3"):
-                result = DDRBufferVirtex2(buffer.direction, buffer.port)
+                result = DDRBufferVirtex2(buffer.direction, buffer.port,
+                                          i_domain=buffer.i_domain,
+                                          o_domain=buffer.o_domain)
             elif self.family in ("spartan3e", "spartan3a", "spartan3adsp", "spartan6"):
-                result = DDRBufferSpartan3E(buffer.direction, buffer.port)
+                result = DDRBufferSpartan3E(buffer.direction, buffer.port,
+                                            i_domain=buffer.i_domain,
+                                            o_domain=buffer.o_domain)
             elif self.family in ("virtex4", "virtex5", "virtex6", "series7"):
-                result = DDRBufferVirtex4(buffer.direction, buffer.port)
+                result = DDRBufferVirtex4(buffer.direction, buffer.port,
+                                          i_domain=buffer.i_domain,
+                                          o_domain=buffer.o_domain)
             elif self.family in ("ultrascale", "ultrascaleplus"):
-                result = DDRBufferUltrascale(buffer.direction, buffer.port)
+                result = DDRBufferUltrascale(buffer.direction, buffer.port,
+                                             i_domain=buffer.i_domain,
+                                             o_domain=buffer.o_domain)
             else:
                 raise TypeError(f"Family {self.family} doesn't implement DDR buffers")
         else: