diff --git a/ArmPlatformPkg/ArmRealViewEbPkg/Library/ArmRealViewEbLibRTSM/ArmRealViewEbMem.c b/ArmPlatformPkg/ArmRealViewEbPkg/Library/ArmRealViewEbLibRTSM/ArmRealViewEbMem.c
index d1a55a8360..c7a413dc2e 100644
--- a/ArmPlatformPkg/ArmRealViewEbPkg/Library/ArmRealViewEbLibRTSM/ArmRealViewEbMem.c
+++ b/ArmPlatformPkg/ArmRealViewEbPkg/Library/ArmRealViewEbLibRTSM/ArmRealViewEbMem.c
@@ -114,21 +114,3 @@ ArmPlatformGetVirtualMemoryMap (
 
   *VirtualMemoryMap = VirtualMemoryTable;
 }
-
-/**
-  Return the EFI Memory Map of your platform
-
-  This EFI Memory Map of the System Memory is used by MemoryInitPei module to create the Resource
-  Descriptor HOBs used by DXE core.
-
-  @param[out]   EfiMemoryMap        Array of ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR describing an
-                                    EFI Memory region. This array must be ended by a zero-filled entry
-
-**/
-EFI_STATUS
-ArmPlatformGetAdditionalSystemMemory (
-  OUT ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR** EfiMemoryMap
-  )
-{
-  return EFI_UNSUPPORTED;
-}
diff --git a/ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibCTA15-A7/CTA15-A7Mem.c b/ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibCTA15-A7/CTA15-A7Mem.c
index 7698aa61ff..d71e58ae89 100644
--- a/ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibCTA15-A7/CTA15-A7Mem.c
+++ b/ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibCTA15-A7/CTA15-A7Mem.c
@@ -174,21 +174,3 @@ ArmPlatformGetVirtualMemoryMap (
 
   *VirtualMemoryMap = VirtualMemoryTable;
 }
-
-/**
-  Return the EFI Memory Map provided by extension memory on your platform
-
-  This EFI Memory Map of the System Memory is used by MemoryInitPei module to create the Resource
-  Descriptor HOBs used by DXE core.
-
-  @param[out]   EfiMemoryMap        Array of ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR describing an
-                                    EFI Memory region. This array must be ended by a zero-filled entry
-
-**/
-EFI_STATUS
-ArmPlatformGetAdditionalSystemMemory (
-  OUT ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR** EfiMemoryMap
-  )
-{
-  return EFI_UNSUPPORTED;
-}
diff --git a/ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibCTA9x4/CTA9x4Mem.c b/ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibCTA9x4/CTA9x4Mem.c
index ef8fa4191a..f647d2575a 100644
--- a/ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibCTA9x4/CTA9x4Mem.c
+++ b/ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibCTA9x4/CTA9x4Mem.c
@@ -117,21 +117,3 @@ ArmPlatformGetVirtualMemoryMap (
 
   *VirtualMemoryMap = VirtualMemoryTable;
 }
-
-/**
-  Return the EFI Memory Map provided by extension memory on your platform
-
-  This EFI Memory Map of the System Memory is used by MemoryInitPei module to create the Resource
-  Descriptor HOBs used by DXE core.
-
-  @param[out]   EfiMemoryMap        Array of ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR describing an
-                                    EFI Memory region. This array must be ended by a zero-filled entry
-
-**/
-EFI_STATUS
-ArmPlatformGetAdditionalSystemMemory (
-  OUT ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR** EfiMemoryMap
-  )
-{
-  return EFI_UNSUPPORTED;
-}
diff --git a/ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibRTSM/RTSMMem.c b/ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibRTSM/RTSMMem.c
index cb6376f65e..68efde7065 100644
--- a/ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibRTSM/RTSMMem.c
+++ b/ArmPlatformPkg/ArmVExpressPkg/Library/ArmVExpressLibRTSM/RTSMMem.c
@@ -126,22 +126,3 @@ ArmPlatformGetVirtualMemoryMap (
 
   *VirtualMemoryMap = VirtualMemoryTable;
 }
-
-/**
-  Return the EFI Memory Map provided by extension memory on your platform
-
-  This EFI Memory Map of the System Memory is used by MemoryInitPei module to create the Resource
-  Descriptor HOBs used by DXE core.
-  TODO: CompleteMe .... say this is the memory not covered by the System Memory PCDs
-
-  @param[out]   EfiMemoryMap        Array of ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR describing an
-                                    EFI Memory region. This array must be ended by a zero-filled entry
-
-**/
-EFI_STATUS
-ArmPlatformGetAdditionalSystemMemory (
-  OUT ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR** EfiMemoryMap
-  )
-{
-  return EFI_UNSUPPORTED;
-}
diff --git a/ArmPlatformPkg/Include/Library/ArmPlatformLib.h b/ArmPlatformPkg/Include/Library/ArmPlatformLib.h
index 7bbd966470..3f6c1517b0 100644
--- a/ArmPlatformPkg/Include/Library/ArmPlatformLib.h
+++ b/ArmPlatformPkg/Include/Library/ArmPlatformLib.h
@@ -97,21 +97,6 @@ ArmPlatformGetVirtualMemoryMap (
   OUT ARM_MEMORY_REGION_DESCRIPTOR** VirtualMemoryMap
   );
 
-/**
-  Return the EFI Memory Map of your platform
-
-  This EFI Memory Map of the System Memory is used by MemoryInitPei module to create the Resource
-  Descriptor HOBs used by DXE core.
-
-  @param[out]   EfiMemoryMap        Array of ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR describing an
-                                    EFI Memory region. This array must be ended by a zero-filled entry
-
-**/
-EFI_STATUS
-ArmPlatformGetAdditionalSystemMemory (
-  OUT ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR** EfiMemoryMap
-  );
-
 /**
   Return the Platform specific PPIs
 
diff --git a/ArmPlatformPkg/Library/ArmPlatformLibNull/ArmPlatformLibNullMem.c b/ArmPlatformPkg/Library/ArmPlatformLibNull/ArmPlatformLibNullMem.c
index 3b44f82f39..aafb797683 100644
--- a/ArmPlatformPkg/Library/ArmPlatformLibNull/ArmPlatformLibNullMem.c
+++ b/ArmPlatformPkg/Library/ArmPlatformLibNull/ArmPlatformLibNullMem.c
@@ -32,21 +32,3 @@ ArmPlatformGetVirtualMemoryMap (
 {
   ASSERT(0);
 }
-
-/**
-  Return the EFI Memory Map of your platform
-
-  This EFI Memory Map of the System Memory is used by MemoryInitPei module to create the Resource
-  Descriptor HOBs used by DXE core.
-
-  @param[out]   EfiMemoryMap        Array of ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR describing an
-                                    EFI Memory region. This array must be ended by a zero-filled entry
-
-**/
-EFI_STATUS
-ArmPlatformGetAdditionalSystemMemory (
-  OUT ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR** EfiMemoryMap
-  )
-{
-  return EFI_UNSUPPORTED;
-}
diff --git a/BeagleBoardPkg/Library/BeagleBoardLib/BeagleBoardMem.c b/BeagleBoardPkg/Library/BeagleBoardLib/BeagleBoardMem.c
index 6af30730ed..5524ddbcad 100755
--- a/BeagleBoardPkg/Library/BeagleBoardLib/BeagleBoardMem.c
+++ b/BeagleBoardPkg/Library/BeagleBoardLib/BeagleBoardMem.c
@@ -82,21 +82,3 @@ ArmPlatformGetVirtualMemoryMap (
 
   *VirtualMemoryMap = VirtualMemoryTable;
 }
-
-/**
-  Return the EFI Memory Map of your platform
-
-  This EFI Memory Map of the System Memory is used by MemoryInitPei module to create the Resource
-  Descriptor HOBs used by DXE core.
-
-  @param[out]   EfiMemoryMap        Array of ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR describing an
-                                    EFI Memory region. This array must be ended by a zero-filled entry
-
-**/
-EFI_STATUS
-ArmPlatformGetAdditionalSystemMemory (
-  OUT ARM_SYSTEM_MEMORY_REGION_DESCRIPTOR** EfiMemoryMap
-  )
-{
-  return EFI_UNSUPPORTED;
-}