diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/Connect.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/Connect.c
index dd3d4a6a27..dd868a7016 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/Connect.c
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/Connect.c
@@ -113,7 +113,6 @@ ShellConnectPciRootBridge (
   @retval EFI_SUCCESS             The operation was successful.
 **/
 EFI_STATUS
-EFIAPI
 ConnectControllers (
   IN CONST EFI_HANDLE ControllerHandle OPTIONAL,
   IN CONST EFI_HANDLE DriverHandle OPTIONAL,
@@ -194,7 +193,6 @@ ConnectControllers (
   @retval EFI_SUCCESS   The operation was successful.
 **/
 EFI_STATUS
-EFIAPI
 ShellConnectFromDevPaths (
   IN CONST CHAR16 *Key
   )
@@ -353,7 +351,6 @@ ShellConnectFromDevPaths (
   @retval EFI_SUCCESS           The operation was successful.
 **/
 EFI_STATUS
-EFIAPI
 ConvertAndConnectControllers (
   IN EFI_HANDLE     *Handle1 OPTIONAL,
   IN EFI_HANDLE     *Handle2 OPTIONAL,
diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/DevTree.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/DevTree.c
index 237cb85f94..6f070eeaa1 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/DevTree.c
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/DevTree.c
@@ -34,7 +34,6 @@ STATIC CONST SHELL_PARAM_ITEM ParamList[] = {
   @retval SHELL_SUCCESS     The operation was successful.
 **/
 SHELL_STATUS
-EFIAPI
 DoDevTreeForHandle(
   IN CONST EFI_HANDLE TheHandle,
   IN CONST CHAR8      *Lang OPTIONAL,
diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/Devices.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/Devices.c
index d229b352c8..b725178ebd 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/Devices.c
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/Devices.c
@@ -42,7 +42,6 @@
   @retval EFI_INVALID_PARAMETER A parameter was invalid.
 **/
 EFI_STATUS
-EFIAPI
 GetDeviceHandleInfo (
   IN EFI_HANDLE   TheHandle,
   IN OUT CHAR16   *Type,
diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/Dh.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/Dh.c
index 0a1b9a9206..00a4c10edc 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/Dh.c
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/Dh.c
@@ -53,7 +53,6 @@ STATIC CONST EFI_GUID *UefiDriverModelProtocolsGuidArray[] = {
   @retval EFI_SUCCESS     The name was found.
 **/
 EFI_STATUS
-EFIAPI
 GetDriverName (
   IN EFI_HANDLE   TheHandle,
   IN CONST CHAR8  *Language,
@@ -107,7 +106,6 @@ GetDriverName (
   @retval FALSE     The guid does not represent a driver model protocol.
 **/
 BOOLEAN
-EFIAPI
 IsDriverProt (
   IN CONST EFI_GUID *Guid
   )
@@ -140,7 +138,6 @@ IsDriverProt (
   @retval SHELL_INVALID_PARAMETER ProtocolName was NULL or invalid.
 **/
 CHAR16*
-EFIAPI
 GetProtocolInfoString(
   IN CONST EFI_HANDLE TheHandle,
   IN CONST CHAR8      *Language,
@@ -217,7 +214,6 @@ GetProtocolInfoString(
   @retval EFI_SUCCESS     The operation was successful.
 **/
 EFI_STATUS
-EFIAPI
 GetDriverImageName (
   IN EFI_HANDLE   TheHandle,
   OUT CHAR16      **Name
@@ -256,7 +252,6 @@ GetDriverImageName (
   @param[in] Language   The language to output in.
 **/
 EFI_STATUS
-EFIAPI
 DisplayDriverModelHandle (
   IN EFI_HANDLE  Handle,
   IN BOOLEAN     BestName,
@@ -648,7 +643,6 @@ DisplayDriverModelHandle (
   @retval SHELL_INVALID_PARAMETER ProtocolName was NULL or invalid.
 **/
 SHELL_STATUS
-EFIAPI
 DoDhByHandle(
   IN CONST EFI_HANDLE TheHandle,
   IN CONST BOOLEAN    Verbose,
@@ -729,7 +723,6 @@ DoDhByHandle(
   @retval SHELL_INVALID_PARAMETER ProtocolName was NULL or invalid.
 **/
 SHELL_STATUS
-EFIAPI
 DoDhForHandleList(
   IN CONST EFI_HANDLE *HandleList,
   IN CONST BOOLEAN    Verbose,
@@ -772,7 +765,6 @@ DoDhForHandleList(
   @retval SHELL_INVALID_PARAMETER ProtocolName was NULL or invalid.
 **/
 SHELL_STATUS
-EFIAPI
 DoDhForAll(
   IN CONST BOOLEAN  Sfo,
   IN CONST BOOLEAN  Verbose,
@@ -810,7 +802,6 @@ DoDhForAll(
   @retval SHELL_INVALID_PARAMETER ProtocolName was NULL or invalid.
 **/
 SHELL_STATUS
-EFIAPI
 DoDhByProtocol(
   IN CONST CHAR16   *ProtocolName,
   IN CONST BOOLEAN  Verbose,
diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/Disconnect.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/Disconnect.c
index adca80ed61..1fd7b196e6 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/Disconnect.c
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/Disconnect.c
@@ -28,7 +28,6 @@ STATIC CONST SHELL_PARAM_ITEM ParamList[] = {
   @retval EFI_SUCCESS     The operation was successful.
 **/
 EFI_STATUS
-EFIAPI
 DisconnectAll(
   VOID
   )
diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/Drivers.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/Drivers.c
index d6d75f0625..ffdef04352 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/Drivers.c
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/Drivers.c
@@ -33,7 +33,6 @@ STATIC CONST SHELL_PARAM_ITEM ParamList[] = {
                   free this memory.
 **/
 CHAR16*
-EFIAPI
 GetDevicePathTextForHandle(
   IN EFI_HANDLE TheHandle
   )
@@ -98,7 +97,6 @@ GetDevicePathTextForHandle(
   @retval FALSE             The driver does not have Driver Configuration.
 **/
 BOOLEAN
-EFIAPI
 ReturnDriverConfig(
   IN CONST EFI_HANDLE TheHandle
   )
@@ -120,7 +118,6 @@ ReturnDriverConfig(
   @retval FALSE             The driver does not have Driver Diagnostics.
 **/
 BOOLEAN
-EFIAPI
 ReturnDriverDiag(
   IN CONST EFI_HANDLE TheHandle
   )
@@ -145,7 +142,6 @@ ReturnDriverDiag(
   @retval 0xFFFFFFFF  An error ocurred.
 **/
 UINT32
-EFIAPI
 ReturnDriverVersion(
   IN CONST EFI_HANDLE TheHandle
   )
diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/DrvCfg.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/DrvCfg.c
index cc1c9ca188..37501d4d3f 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/DrvCfg.c
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/DrvCfg.c
@@ -30,7 +30,6 @@ STATIC CONST EFI_GUID *CfgGuidList[] = {&gEfiDriverConfigurationProtocolGuid, &g
   @retval EFI_NOT_FOUND   There was no EFI_HII_HANDLE found for that deviec path.
 **/
 EFI_STATUS
-EFIAPI
 FindHiiHandleViaDevPath(
   IN CONST EFI_DEVICE_PATH_PROTOCOL *DevPath1,
   OUT EFI_HII_HANDLE                *HiiHandle,
@@ -124,7 +123,6 @@ FindHiiHandleViaDevPath(
   @retval EFI_SUCCESS   The operation was successful.
 **/
 EFI_STATUS
-EFIAPI
 ConvertHandleToHiiHandle(
   IN CONST EFI_HANDLE           Handle,
   OUT EFI_HII_HANDLE            *HiiHandle,
@@ -159,7 +157,6 @@ ConvertHandleToHiiHandle(
   @param[in] FileName         The filename to rwite the info to.
 **/
 SHELL_STATUS
-EFIAPI
 ConfigToFile(
   IN CONST EFI_HANDLE     Handle,
   IN CONST CHAR16         *FileName
@@ -269,7 +266,6 @@ ConfigToFile(
   @param[in] FileName         The filename to read the info from.
 **/
 SHELL_STATUS
-EFIAPI
 ConfigFromFile(
   IN       EFI_HANDLE     Handle,
   IN CONST CHAR16         *FileName
@@ -486,7 +482,6 @@ ConfigFromFile(
   @retval SHELL_INVALID_PARAMETER   A parameter has a invalid value.
 **/
 EFI_STATUS
-EFIAPI
 ShellCmdDriverConfigurationProcessActionRequired (
   EFI_HANDLE                                DriverImageHandle,
   EFI_HANDLE                                ControllerHandle,
@@ -554,7 +549,6 @@ ShellCmdDriverConfigurationProcessActionRequired (
   @retval SHELL_INVALID_PARAMETER   A parameter has a invalid value.
 **/
 SHELL_STATUS
-EFIAPI
 PreHiiDrvCfg (
   IN CONST CHAR8    *Language,
   IN BOOLEAN        ForceDefaults,
@@ -1062,7 +1056,6 @@ Done:
   @retval SHELL_SUCCESS     The operation was successful.
 **/
 SHELL_STATUS
-EFIAPI
 PrintConfigInfoOnAll(
   IN CONST BOOLEAN ChildrenToo,
   IN CONST CHAR8   *Language,
diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/DrvDiag.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/DrvDiag.c
index 04f6a58c3d..cc1099f68f 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/DrvDiag.c
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/DrvDiag.c
@@ -42,7 +42,6 @@ typedef enum {
   @retval EFI_NOT_FOUND         No diagnostic handle could be found.
 **/
 EFI_STATUS
-EFIAPI
 DoDiagnostics (
   IN CONST DRV_DIAG_TEST_MODE Mode,
   IN CONST CHAR8              *Lang,
diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/OpenInfo.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/OpenInfo.c
index e11873aa10..2a1748c514 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/OpenInfo.c
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/OpenInfo.c
@@ -33,7 +33,6 @@ STATIC CONST CHAR16 StringUnknown[]   = L"Unknown  ";
   @retval EFI_INVALID_PARAMETER TheHandle was NULL.
 **/
 EFI_STATUS
-EFIAPI
 TraverseHandleDatabase (
   IN CONST EFI_HANDLE TheHandle
   )
diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.h b/ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.h
index c65d0ed695..7d1a601d75 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.h
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.h
@@ -215,7 +215,6 @@ ShellCommandRunUnload (
   @retval EFI_SUCCESS   The operation was successful.
 **/
 EFI_STATUS
-EFIAPI
 ShellConnectFromDevPaths (
   IN CONST CHAR16 *Key
   );
diff --git a/ShellPkg/Library/UefiShellDriver1CommandsLib/Unload.c b/ShellPkg/Library/UefiShellDriver1CommandsLib/Unload.c
index 0d48f9d5d7..b5f085a750 100644
--- a/ShellPkg/Library/UefiShellDriver1CommandsLib/Unload.c
+++ b/ShellPkg/Library/UefiShellDriver1CommandsLib/Unload.c
@@ -24,7 +24,6 @@
   @retval EFI_INVALID_PARAMETER     The handle did not have LoadedImage
 **/
 EFI_STATUS
-EFIAPI
 DumpLoadedImageProtocolInfo (
   IN EFI_HANDLE   TheHandle
   )