diff --git a/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.inf b/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.inf
index 3c2246fb8a..055a055299 100644
--- a/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.inf
+++ b/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.inf
@@ -52,6 +52,7 @@
   gEmbeddedTokenSpaceGuid.PcdLan9118DxeBaseAddress
   gEmbeddedTokenSpaceGuid.PcdLan9118DefaultMacAddress
   gEmbeddedTokenSpaceGuid.PcdLan9118DefaultNegotiationTimeout
+  gEmbeddedTokenSpaceGuid.PcdLan9118NegotiationFeatureMask
 
 [Depex]
   TRUE
diff --git a/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118DxeUtil.c b/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118DxeUtil.c
index 50c004d728..ea308afe6b 100644
--- a/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118DxeUtil.c
+++ b/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118DxeUtil.c
@@ -648,6 +648,7 @@ AutoNegotiate (
     Features &= ~(PHYANA_PAUSE_OP_MASK);
     Features |= 3 << 10;
   }
+  Features &= FixedPcdGet32 (PcdLan9118NegotiationFeatureMask);
 
   // Write the features
   IndirectPHYWrite32 (PHY_INDEX_AUTO_NEG_ADVERT, Features);
diff --git a/EmbeddedPkg/EmbeddedPkg.dec b/EmbeddedPkg/EmbeddedPkg.dec
index 7bcb1332df..775d863c5f 100644
--- a/EmbeddedPkg/EmbeddedPkg.dec
+++ b/EmbeddedPkg/EmbeddedPkg.dec
@@ -147,6 +147,9 @@
   gEmbeddedTokenSpaceGuid.PcdLan9118DxeBaseAddress|0x0|UINT32|0x00000025
   gEmbeddedTokenSpaceGuid.PcdLan9118DefaultMacAddress|0x0|UINT64|0x00000026
   gEmbeddedTokenSpaceGuid.PcdLan9118DefaultNegotiationTimeout|4000|UINT32|0x00000027
+  # The default feature mask below disables full duplex negotiation, since full
+  # duplex operation is suspected to be broken in the driver.
+  gEmbeddedTokenSpaceGuid.PcdLan9118NegotiationFeatureMask|0xFFFFFEBF|UINT32|0x00000028
 
   #
   # Android FastBoot