diff --git a/migen/bus/wishbone2csr.py b/migen/bus/wishbone2csr.py
index 362cce493..565686181 100644
--- a/migen/bus/wishbone2csr.py
+++ b/migen/bus/wishbone2csr.py
@@ -15,7 +15,7 @@ class WB2CSR():
 	def get_fragment(self):
 		sync = [
 			self.csr.we_o.eq(0),
-			self.csr.d_o.eq(self.wishbone.dat_i),
+			self.csr.d_o.eq(self.wishbone.dat_i[:8]),
 			self.csr.a_o.eq(self.wishbone.adr_i[:14]),
 			self.wishbone.dat_o.eq(self.csr.d_i)
 		]