diff --git a/ShellPkg/Application/Shell/ConsoleLogger.c b/ShellPkg/Application/Shell/ConsoleLogger.c
index 563e5e6be7..bc96da1f1b 100644
--- a/ShellPkg/Application/Shell/ConsoleLogger.c
+++ b/ShellPkg/Application/Shell/ConsoleLogger.c
@@ -29,7 +29,6 @@
   @sa InstallProtocolInterface
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerInstall(
   IN CONST UINTN ScreensToSave,
   OUT CONSOLE_LOGGER_PRIVATE_DATA **ConsoleInfo
@@ -114,7 +113,6 @@ ConsoleLoggerInstall(
   @return other           The operation failed.  This was from UninstallProtocolInterface.
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerUninstall(
   IN CONSOLE_LOGGER_PRIVATE_DATA *ConsoleInfo
   )
@@ -162,7 +160,6 @@ ConsoleLoggerUninstall(
   @param[in] ConsoleInfo  The pointer to the instance of the console logger information.
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerDisplayHistory(
   IN CONST BOOLEAN  Forward,
   IN CONST UINTN    Rows,
@@ -238,7 +235,6 @@ ConsoleLoggerDisplayHistory(
   @sa UpdateDisplayFromHistory
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerStopHistory(
   IN CONSOLE_LOGGER_PRIVATE_DATA *ConsoleInfo
   )
@@ -265,7 +261,6 @@ ConsoleLoggerStopHistory(
   @return other           The operation failed.
 **/
 EFI_STATUS
-EFIAPI
 UpdateDisplayFromHistory(
   IN CONSOLE_LOGGER_PRIVATE_DATA *ConsoleInfo
   )
@@ -454,7 +449,6 @@ ConsoleLoggerReset (
   @param[in] ConsoleInfo  The pointer to the instance of the console logger information.
 **/
 EFI_STATUS
-EFIAPI
 AppendStringToHistory(
   IN CONST CHAR16 *String,
   IN CONSOLE_LOGGER_PRIVATE_DATA *ConsoleInfo
@@ -609,7 +603,6 @@ AppendStringToHistory(
                                   rendered and were skipped.
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerOutputStringSplit(
   IN CONST CHAR16   *String,
   IN CONSOLE_LOGGER_PRIVATE_DATA *ConsoleInfo
@@ -638,7 +631,6 @@ ConsoleLoggerOutputStringSplit(
   @return other         Break was choosen
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerDoPageBreak(
   VOID
   )
@@ -697,7 +689,6 @@ ConsoleLoggerDoPageBreak(
                                   rendered and were skipped.
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerPrintWithPageBreak(
   IN CONST CHAR16   *String,
   IN CONSOLE_LOGGER_PRIVATE_DATA *ConsoleInfo
@@ -1208,7 +1199,6 @@ ConsoleLoggerEnableCursor (
   history buffers.
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerResetBuffers(
   IN CONSOLE_LOGGER_PRIVATE_DATA *ConsoleInfo
   )
diff --git a/ShellPkg/Application/Shell/ConsoleLogger.h b/ShellPkg/Application/Shell/ConsoleLogger.h
index 19034c9050..881c24b790 100644
--- a/ShellPkg/Application/Shell/ConsoleLogger.h
+++ b/ShellPkg/Application/Shell/ConsoleLogger.h
@@ -58,7 +58,6 @@ typedef struct _CONSOLE_LOGGER_PRIVATE_DATA{
   @sa InstallProtocolInterface
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerInstall(
   IN CONST UINTN ScreensToSave,
   OUT CONSOLE_LOGGER_PRIVATE_DATA **ConsoleInfo
@@ -74,7 +73,6 @@ ConsoleLoggerInstall(
   @return other           The operation failed.  This was from UninstallProtocolInterface.
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerUninstall(
   IN OUT CONSOLE_LOGGER_PRIVATE_DATA *ConsoleInfo
   );
@@ -92,7 +90,6 @@ ConsoleLoggerUninstall(
   @param[in] ConsoleInfo  The pointer to the instance of the console logger information.
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerDisplayHistory(
   IN CONST BOOLEAN  Forward,
   IN CONST UINTN    Rows,
@@ -109,7 +106,6 @@ ConsoleLoggerDisplayHistory(
   @sa UpdateDisplayFromHistory
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerStopHistory(
   IN CONSOLE_LOGGER_PRIVATE_DATA *ConsoleInfo
   );
@@ -122,7 +118,6 @@ ConsoleLoggerStopHistory(
   @return other           The operation failed.
 **/
 EFI_STATUS
-EFIAPI
 UpdateDisplayFromHistory(
   IN CONSOLE_LOGGER_PRIVATE_DATA *ConsoleInfo
   );
@@ -320,7 +315,6 @@ ConsoleLoggerEnableCursor (
   history buffers.
 **/
 EFI_STATUS
-EFIAPI
 ConsoleLoggerResetBuffers(
   IN CONSOLE_LOGGER_PRIVATE_DATA *ConsoleInfo
   );
diff --git a/ShellPkg/Application/Shell/ConsoleWrappers.c b/ShellPkg/Application/Shell/ConsoleWrappers.c
index 46af141eba..e1846ec9cb 100644
--- a/ShellPkg/Application/Shell/ConsoleWrappers.c
+++ b/ShellPkg/Application/Shell/ConsoleWrappers.c
@@ -133,7 +133,6 @@ FileBasedSimpleTextInReadKeyStroke(
   @return                     A pointer to the allocated protocol structure;
 **/
 EFI_SIMPLE_TEXT_INPUT_PROTOCOL*
-EFIAPI
 CreateSimpleTextInOnFile(
   IN SHELL_FILE_HANDLE  FileHandleToUse,
   IN EFI_HANDLE         *HandleLocation
@@ -200,7 +199,6 @@ CreateSimpleTextInOnFile(
   @retval EFI_SUCCESS         The object was closed.
 **/
 EFI_STATUS
-EFIAPI
 CloseSimpleTextInOnFile(
   IN EFI_SIMPLE_TEXT_INPUT_PROTOCOL  *SimpleTextIn
   )
@@ -434,7 +432,6 @@ FileBasedSimpleTextOutOutputString (
   @return                     A pointer to the allocated protocol structure;
 **/
 EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL*
-EFIAPI
 CreateSimpleTextOutOnFile(
   IN SHELL_FILE_HANDLE               FileHandleToUse,
   IN EFI_HANDLE                      *HandleLocation,
@@ -499,7 +496,6 @@ CreateSimpleTextOutOnFile(
   @retval EFI_SUCCESS         The object was closed.
 **/
 EFI_STATUS
-EFIAPI
 CloseSimpleTextOutOnFile(
   IN EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL  *SimpleTextOut
   )
diff --git a/ShellPkg/Application/Shell/ConsoleWrappers.h b/ShellPkg/Application/Shell/ConsoleWrappers.h
index ecd99a863d..35f3a717f5 100644
--- a/ShellPkg/Application/Shell/ConsoleWrappers.h
+++ b/ShellPkg/Application/Shell/ConsoleWrappers.h
@@ -27,7 +27,6 @@
   @return                     A pointer to the allocated protocol structure;
 **/
 EFI_SIMPLE_TEXT_INPUT_PROTOCOL*
-EFIAPI
 CreateSimpleTextInOnFile(
   IN SHELL_FILE_HANDLE  FileHandleToUse,
   IN EFI_HANDLE         *HandleLocation
@@ -42,7 +41,6 @@ CreateSimpleTextInOnFile(
   @retval EFI_SUCCESS         The object was closed.
 **/
 EFI_STATUS
-EFIAPI
 CloseSimpleTextInOnFile(
   IN EFI_SIMPLE_TEXT_INPUT_PROTOCOL  *SimpleTextIn
   );
@@ -59,7 +57,6 @@ CloseSimpleTextInOnFile(
   @return                     A pointer to the allocated protocol structure;
 **/
 EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL*
-EFIAPI
 CreateSimpleTextOutOnFile(
   IN SHELL_FILE_HANDLE               FileHandleToUse,
   IN EFI_HANDLE                      *HandleLocation,
@@ -75,7 +72,6 @@ CreateSimpleTextOutOnFile(
   @retval EFI_SUCCESS         The object was closed.
 **/
 EFI_STATUS
-EFIAPI
 CloseSimpleTextOutOnFile(
   IN EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL  *SimpleTextOut
   );
diff --git a/ShellPkg/Application/Shell/FileHandleInternal.h b/ShellPkg/Application/Shell/FileHandleInternal.h
index 11b490267c..1e51980856 100644
--- a/ShellPkg/Application/Shell/FileHandleInternal.h
+++ b/ShellPkg/Application/Shell/FileHandleInternal.h
@@ -23,7 +23,6 @@
   @param[in, out] Row         Current row of the cursor position
 **/
 VOID
-EFIAPI
 MoveCursorBackward (
   IN     UINTN                   LineLength,
   IN OUT UINTN                   *Column,
@@ -39,7 +38,6 @@ MoveCursorBackward (
   @param[in, out] Row         Current row of the cursor position
 **/
 VOID
-EFIAPI
 MoveCursorForward (
   IN     UINTN                   LineLength,
   IN     UINTN                   TotalRow,
@@ -57,7 +55,6 @@ MoveCursorForward (
   @param[in] StartColumn  which column to start at
 **/
 VOID
-EFIAPI
 PrintCommandHistory (
   IN CONST UINTN TotalCols,
   IN CONST UINTN TotalRows,
diff --git a/ShellPkg/Application/Shell/FileHandleWrappers.c b/ShellPkg/Application/Shell/FileHandleWrappers.c
index 0d38e9d5fe..9a75a686a4 100644
--- a/ShellPkg/Application/Shell/FileHandleWrappers.c
+++ b/ShellPkg/Application/Shell/FileHandleWrappers.c
@@ -302,7 +302,6 @@ FileInterfaceNulWrite(
   @param[out] TabUpdatePos      Return the TAB update position.
 **/
 EFI_STATUS
-EFIAPI
 CreateTabCompletionList (
   IN CONST CHAR16             *InputString,
   IN CONST UINTN              StringLen, 
@@ -1227,7 +1226,6 @@ FileInterfaceEnvNonVolWrite(
   @return other     a pointer to an EFI_FILE_PROTOCOL structure
 **/
 EFI_FILE_PROTOCOL*
-EFIAPI
 CreateFileInterfaceEnv(
   IN CONST CHAR16 *EnvName
   )
@@ -1290,7 +1288,6 @@ CreateFileInterfaceEnv(
   @param[in, out] Row         Current row of the cursor position
 **/
 VOID
-EFIAPI
 MoveCursorBackward (
   IN     UINTN                   LineLength,
   IN OUT UINTN                   *Column,
@@ -1320,7 +1317,6 @@ MoveCursorBackward (
   @param[in, out] Row         Current row of the cursor position
 **/
 VOID
-EFIAPI
 MoveCursorForward (
   IN     UINTN                   LineLength,
   IN     UINTN                   TotalRow,
@@ -1352,7 +1348,6 @@ MoveCursorForward (
   @param[in] StartColumn  which column to start at
 **/
 VOID
-EFIAPI
 PrintCommandHistory (
   IN CONST UINTN TotalCols,
   IN CONST UINTN TotalRows,
@@ -1576,7 +1571,6 @@ FileInterfaceMemClose(
   @return other     A pointer to an EFI_FILE_PROTOCOL structure.
 **/
 EFI_FILE_PROTOCOL*
-EFIAPI
 CreateFileInterfaceMem(
   IN CONST BOOLEAN Unicode
   )
diff --git a/ShellPkg/Application/Shell/FileHandleWrappers.h b/ShellPkg/Application/Shell/FileHandleWrappers.h
index af133b0963..9034d696e1 100644
--- a/ShellPkg/Application/Shell/FileHandleWrappers.h
+++ b/ShellPkg/Application/Shell/FileHandleWrappers.h
@@ -55,7 +55,6 @@ extern EFI_FILE_PROTOCOL FileInterfaceNulFile;
   @return other     a pointer to an EFI_FILE_PROTOCOL structure
 **/
 EFI_FILE_PROTOCOL*
-EFIAPI
 CreateFileInterfaceEnv(
   CONST CHAR16 *EnvName
   );
@@ -70,7 +69,6 @@ CreateFileInterfaceEnv(
   @return other     a pointer to an EFI_FILE_PROTOCOL structure
 **/
 EFI_FILE_PROTOCOL*
-EFIAPI
 CreateFileInterfaceMem(
   IN CONST BOOLEAN Unicode
   );
diff --git a/ShellPkg/Application/Shell/Shell.c b/ShellPkg/Application/Shell/Shell.c
index 0b6362e926..b39d81d0ee 100644
--- a/ShellPkg/Application/Shell/Shell.c
+++ b/ShellPkg/Application/Shell/Shell.c
@@ -80,7 +80,6 @@ CONST CHAR16 mNoNestingFalse[]              = L"False";
   @param[in] String pointer to the string to trim them off.
 **/
 EFI_STATUS
-EFIAPI
 TrimSpaces(
   IN CHAR16 **String
   )
@@ -113,7 +112,6 @@ TrimSpaces(
   @param[in] CheckForEscapeCharacter  TRUE to skip escaped instances of FinfString, otherwise will return even escaped instances
 **/
 CHAR16*
-EFIAPI
 FindNextInstance(
   IN CONST CHAR16   *SourceString,
   IN CONST CHAR16   *FindString,
@@ -202,7 +200,6 @@ IsValidEnvironmentVariableName(
   @retval FALSE           CmdLine does not have a valid split.
 **/
 BOOLEAN
-EFIAPI
 ContainsSplit(
   IN CONST CHAR16 *CmdLine
   )
@@ -252,7 +249,6 @@ ContainsSplit(
   @retval EFI_OUT_OF_RESOURCES  There is not enough memory available.
 **/
 EFI_STATUS
-EFIAPI
 InternalEfiShellStartCtrlSMonitor(
   VOID
   )
@@ -729,7 +725,6 @@ FreeResources:
   @retval EFI_SUCCESS           all init commands were run successfully.
 **/
 EFI_STATUS
-EFIAPI
 SetBuiltInAlias(
   )
 {
@@ -768,7 +763,6 @@ SetBuiltInAlias(
   @retval FALSE             The 2 command names are not the same.
 **/
 BOOLEAN
-EFIAPI
 IsCommand(
   IN CONST CHAR16 *Command1,
   IN CONST CHAR16 *Command2
@@ -789,7 +783,6 @@ IsCommand(
   @retval FALSE             The command is not a script only command.
 **/
 BOOLEAN
-EFIAPI
 IsScriptOnlyCommand(
   IN CONST CHAR16 *CommandName
   )
@@ -820,7 +813,6 @@ IsScriptOnlyCommand(
   @sa HandleProtocol
 **/
 EFI_STATUS
-EFIAPI
 GetDevicePathsForImageAndFile (
   IN OUT EFI_DEVICE_PATH_PROTOCOL **DevPath,
   IN OUT EFI_DEVICE_PATH_PROTOCOL **FilePath
@@ -896,7 +888,6 @@ GetDevicePathsForImageAndFile (
   @retval EFI_SUCCESS           The variable is initialized.
 **/
 EFI_STATUS
-EFIAPI
 ProcessCommandLine(
   VOID
   )
@@ -1103,7 +1094,6 @@ ProcessCommandLine(
   @retval EFI_SUCCESS           the variable is initialized.
 **/
 EFI_STATUS
-EFIAPI
 DoStartupScript(
   IN EFI_DEVICE_PATH_PROTOCOL *ImagePath,
   IN EFI_DEVICE_PATH_PROTOCOL *FilePath
@@ -1251,7 +1241,6 @@ DoStartupScript(
   @retval RETURN_ABORTED
 **/
 EFI_STATUS
-EFIAPI
 DoShellPrompt (
   VOID
   )
@@ -1318,7 +1307,6 @@ DoShellPrompt (
   @param Buffer   Something to pass to FreePool when the shell is exiting.
 **/
 VOID*
-EFIAPI
 AddBufferToFreeList (
   VOID *Buffer
   )
@@ -1375,7 +1363,6 @@ RestoreBufferList (
   @param Buffer     The line buffer to add.
 **/
 VOID
-EFIAPI
 AddLineToCommandHistory(
   IN CONST CHAR16 *Buffer
   )
@@ -1437,7 +1424,6 @@ AddLineToCommandHistory(
   @retval EFI_OUT_OF_RESOURCES    A memory allocation failed.
 **/
 EFI_STATUS
-EFIAPI
 ShellConvertAlias(
   IN OUT CHAR16 **CommandString
   )
@@ -1462,7 +1448,6 @@ ShellConvertAlias(
   @param[in,out] CmdLine   The command line to update.
 **/
 EFI_STATUS
-EFIAPI
 StripUnreplacedEnvironmentVariables(
   IN OUT CHAR16 *CmdLine
   )
@@ -1535,7 +1520,6 @@ StripUnreplacedEnvironmentVariables(
   @return                           The new command line with no environment variables present.
 **/
 CHAR16*
-EFIAPI
 ShellConvertVariables (
   IN CONST CHAR16 *OriginalCommandLine
   )
@@ -1671,7 +1655,6 @@ ShellConvertVariables (
   @retval other             Some error occurs when executing the split command.
 **/
 EFI_STATUS
-EFIAPI
 RunSplitCommand(
   IN CONST CHAR16             *CmdLine,
   IN       SHELL_FILE_HANDLE  *StdIn,
@@ -1790,7 +1773,6 @@ RunSplitCommand(
   @retval EFI_OUT_OF_RESOURCES  a memory allocation failed.
 **/
 EFI_STATUS
-EFIAPI
 ShellSubstituteVariables(
   IN CHAR16 **CmdLine
   )
@@ -1815,7 +1797,6 @@ ShellSubstituteVariables(
   @retval EFI_OUT_OF_RESOURCES  a memory allocation failed.
 **/
 EFI_STATUS
-EFIAPI
 ShellSubstituteAliases(
   IN CHAR16 **CmdLine
   )
@@ -1887,7 +1868,6 @@ ShellSubstituteAliases(
   @retval Efi_Application     the name is an application (.EFI).
 **/
 SHELL_OPERATION_TYPES
-EFIAPI
 GetOperationType(
   IN CONST CHAR16 *CmdName
   )
@@ -1956,7 +1936,6 @@ GetOperationType(
   @retval EFI_NOT_FOUND         The operation type is unknown or invalid.
 **/
 EFI_STATUS 
-EFIAPI
 IsValidSplit(
   IN CONST CHAR16 *CmdLine
   )
@@ -2015,7 +1994,6 @@ IsValidSplit(
   @retval EFI_ABORTED     CmdLine has at least one invalid command or application.
 **/
 EFI_STATUS
-EFIAPI
 VerifySplit(
   IN CONST CHAR16 *CmdLine
   )
@@ -2061,7 +2039,6 @@ VerifySplit(
   @return               an error occurred.
 **/
 EFI_STATUS
-EFIAPI
 ProcessNewSplitCommandLine(
   IN CONST CHAR16 *CmdLine
   )
@@ -2102,7 +2079,6 @@ ProcessNewSplitCommandLine(
   @retval EFI_SUCCESS The operation was successful.
 **/
 EFI_STATUS
-EFIAPI
 ChangeMappedDrive(
   IN CONST CHAR16 *CmdLine
   )
@@ -2138,7 +2114,6 @@ ChangeMappedDrive(
   @param[in,out] CmdLine        pointer to the command line to update
 **/
 EFI_STATUS
-EFIAPI
 DoHelpUpdate(
   IN OUT CHAR16 **CmdLine
   )
@@ -2192,7 +2167,6 @@ DoHelpUpdate(
   @param[in] ErrorCode      the error code to put into lasterror.
 **/
 EFI_STATUS
-EFIAPI
 SetLastError(
   IN CONST SHELL_STATUS   ErrorCode
   )
@@ -2219,7 +2193,6 @@ SetLastError(
   @return                       some other error occurred
 **/
 EFI_STATUS
-EFIAPI
 ProcessCommandLineToFinal(
   IN OUT CHAR16 **CmdLine
   )
@@ -2272,7 +2245,6 @@ ProcessCommandLineToFinal(
   @retval EFI_ABORTED     The command's operation was aborted.
 **/
 EFI_STATUS
-EFIAPI
 RunInternalCommand(
   IN CONST CHAR16                   *CmdLine,
   IN       CHAR16                   *FirstParameter,
@@ -2385,7 +2357,6 @@ RunInternalCommand(
   @retval EFI_ABORTED     The command's operation was aborted.
 **/
 EFI_STATUS
-EFIAPI
 RunCommandOrFile(
   IN       SHELL_OPERATION_TYPES    Type,
   IN CONST CHAR16                   *CmdLine,
@@ -2515,7 +2486,6 @@ RunCommandOrFile(
   @retval EFI_ABORTED     The command's operation was aborted.
 **/
 EFI_STATUS
-EFIAPI
 SetupAndRunCommandOrFile(
   IN   SHELL_OPERATION_TYPES          Type,
   IN   CHAR16                         *CmdLine,
@@ -2578,7 +2548,6 @@ SetupAndRunCommandOrFile(
   @retval EFI_ABORTED     The command's operation was aborted.
 **/
 EFI_STATUS
-EFIAPI
 RunShellCommand(
   IN CONST CHAR16   *CmdLine,
   OUT EFI_STATUS    *CommandStatus
@@ -2699,7 +2668,6 @@ RunShellCommand(
   @retval EFI_ABORTED     The command's operation was aborted.
 **/
 EFI_STATUS
-EFIAPI
 RunCommand(
   IN CONST CHAR16   *CmdLine
   )
@@ -2719,7 +2687,6 @@ STATIC CONST UINT16 InvalidChars[] = {L'*', L'?', L'<', L'>', L'\\', L'/', L'\"'
   @retval FALSE             CommandName could not be a valid command name
 **/
 BOOLEAN
-EFIAPI
 IsValidCommandName(
   IN CONST CHAR16     *CommandName
   )
@@ -2749,7 +2716,6 @@ IsValidCommandName(
   @retval EFI_SUCCESS           the script completed successfully
 **/
 EFI_STATUS
-EFIAPI
 RunScriptFileHandle (
   IN SHELL_FILE_HANDLE  Handle,
   IN CONST CHAR16       *Name
@@ -3067,7 +3033,6 @@ RunScriptFileHandle (
   @retval EFI_SUCCESS           the script completed successfully
 **/
 EFI_STATUS
-EFIAPI
 RunScriptFile (
   IN CONST CHAR16                   *ScriptPath,
   IN SHELL_FILE_HANDLE              Handle OPTIONAL,
@@ -3131,7 +3096,6 @@ RunScriptFile (
   @retval CHAR_NULL no instance of any character in CharacterList was found in String
 **/
 CONST CHAR16*
-EFIAPI
 FindFirstCharacter(
   IN CONST CHAR16 *String,
   IN CONST CHAR16 *CharacterList,
diff --git a/ShellPkg/Application/Shell/Shell.h b/ShellPkg/Application/Shell/Shell.h
index 29b36b003a..a93ea60ad1 100644
--- a/ShellPkg/Application/Shell/Shell.h
+++ b/ShellPkg/Application/Shell/Shell.h
@@ -151,7 +151,6 @@ extern SHELL_INFO ShellInfoObject;
   @return                       some other error occurred
 **/
 EFI_STATUS
-EFIAPI
 ProcessCommandLineToFinal(
   IN OUT CHAR16 **CmdLine
   );
@@ -162,7 +161,6 @@ ProcessCommandLineToFinal(
   @param[in] ErrorCode      the error code to put into lasterror
 **/
 EFI_STATUS
-EFIAPI
 SetLastError(
   IN CONST SHELL_STATUS   ErrorCode
   );
@@ -173,7 +171,6 @@ SetLastError(
   @retval EFI_SUCCESS           all init commands were run successfully.
 **/
 EFI_STATUS
-EFIAPI
 SetBuiltInAlias(
   VOID
   );
@@ -193,7 +190,6 @@ SetBuiltInAlias(
   @sa HandleProtocol
 **/
 EFI_STATUS
-EFIAPI
 GetDevicePathsForImageAndFile (
   IN OUT EFI_DEVICE_PATH_PROTOCOL **DevPath,
   IN OUT EFI_DEVICE_PATH_PROTOCOL **FilePath
@@ -227,7 +223,6 @@ GetDevicePathsForImageAndFile (
   @retval EFI_SUCCESS           the variable is initialized.
 **/
 EFI_STATUS
-EFIAPI
 ProcessCommandLine(
   VOID
   );
@@ -243,7 +238,6 @@ ProcessCommandLine(
   @retval EFI_SUCCESS           The variable is initialized.
 **/
 EFI_STATUS
-EFIAPI
 DoStartupScript(
   IN EFI_DEVICE_PATH_PROTOCOL *ImagePath,
   IN EFI_DEVICE_PATH_PROTOCOL *FilePath
@@ -258,7 +252,6 @@ DoStartupScript(
   @retval RETURN_ABORTED
 **/
 EFI_STATUS
-EFIAPI
 DoShellPrompt (
   VOID
   );
@@ -270,7 +263,6 @@ DoShellPrompt (
   @param Buffer   Something to pass to FreePool when the shell is exiting.
 **/
 VOID*
-EFIAPI
 AddBufferToFreeList(
   VOID *Buffer
   );
@@ -281,7 +273,6 @@ AddBufferToFreeList(
   @param Buffer[in]     The line buffer to add.
 **/
 VOID
-EFIAPI
 AddLineToCommandHistory(
   IN CONST CHAR16 *Buffer
   );
@@ -297,7 +288,6 @@ AddLineToCommandHistory(
   @retval EFI_ABORTED     the command's operation was aborted
 **/
 EFI_STATUS
-EFIAPI
 RunCommand(
   IN CONST CHAR16   *CmdLine
   );
@@ -315,7 +305,6 @@ RunCommand(
   @retval EFI_ABORTED     The command's operation was aborted.
 **/
 EFI_STATUS
-EFIAPI
 RunShellCommand(
   IN CONST CHAR16   *CmdLine,
   OUT EFI_STATUS    *CommandStatus
@@ -331,7 +320,6 @@ RunShellCommand(
   @retval FALSE             CommandName could not be a valid command name
 **/
 BOOLEAN
-EFIAPI
 IsValidCommandName(
   IN CONST CHAR16     *CommandName
   );
@@ -345,7 +333,6 @@ IsValidCommandName(
   @retval EFI_SUCCESS           the script completed successfully
 **/
 EFI_STATUS
-EFIAPI
 RunScriptFileHandle (
   IN SHELL_FILE_HANDLE  Handle,
   IN CONST CHAR16       *Name
@@ -362,7 +349,6 @@ RunScriptFileHandle (
   @retval EFI_SUCCESS           the script completed successfully
 **/
 EFI_STATUS
-EFIAPI
 RunScriptFile (
   IN CONST CHAR16                   *ScriptPath,
   IN SHELL_FILE_HANDLE              Handle OPTIONAL,
@@ -381,7 +367,6 @@ RunScriptFile (
   @retval CHAR_NULL no instance of any character in CharacterList was found in String
 **/
 CONST CHAR16*
-EFIAPI
 FindFirstCharacter(
   IN CONST CHAR16 *String,
   IN CONST CHAR16 *CharacterList,
@@ -394,7 +379,6 @@ FindFirstCharacter(
   @param[in] String pointer to the string to trim them off.
 **/
 EFI_STATUS
-EFIAPI
 TrimSpaces(
   IN CHAR16 **String
   );
diff --git a/ShellPkg/Application/Shell/ShellEnvVar.c b/ShellPkg/Application/Shell/ShellEnvVar.c
index 77bf599eab..6d8c79b4ca 100644
--- a/ShellPkg/Application/Shell/ShellEnvVar.c
+++ b/ShellPkg/Application/Shell/ShellEnvVar.c
@@ -91,7 +91,6 @@ IsVolatileEnv (
   @param[in] List               The pointer to pointer to list.
 **/
 VOID
-EFIAPI
 FreeEnvironmentVariableList(
   IN LIST_ENTRY *List
   )
@@ -128,7 +127,6 @@ FreeEnvironmentVariableList(
   @retval EFI_SUCCESS           the list was created sucessfully.
 **/
 EFI_STATUS
-EFIAPI
 GetEnvironmentVariableList(
   IN OUT LIST_ENTRY *ListHead
   )
@@ -238,7 +236,6 @@ GetEnvironmentVariableList(
   @retval EFI_SUCCESS           the list was Set sucessfully.
 **/
 EFI_STATUS
-EFIAPI
 SetEnvironmentVariableList(
   IN LIST_ENTRY *ListHead
   )
@@ -302,7 +299,6 @@ SetEnvironmentVariableList(
   @sa SetEnvironmentVariableList
 **/
 EFI_STATUS
-EFIAPI
 SetEnvironmentVariables(
   IN CONST CHAR16 **Environment
   )
diff --git a/ShellPkg/Application/Shell/ShellEnvVar.h b/ShellPkg/Application/Shell/ShellEnvVar.h
index f05ef2bd66..b9efed042b 100644
--- a/ShellPkg/Application/Shell/ShellEnvVar.h
+++ b/ShellPkg/Application/Shell/ShellEnvVar.h
@@ -156,7 +156,6 @@ IsVolatileEnv (
   @retval EFI_SUCCESS           the list was created sucessfully.
 **/
 EFI_STATUS
-EFIAPI
 GetEnvironmentVariableList(
   IN OUT LIST_ENTRY *List
   );
@@ -174,7 +173,6 @@ GetEnvironmentVariableList(
   @retval EFI_SUCCESS           The list was Set sucessfully.
 **/
 EFI_STATUS
-EFIAPI
 SetEnvironmentVariableList(
   IN LIST_ENTRY *List
   );
@@ -195,7 +193,6 @@ SetEnvironmentVariableList(
   @sa SetEnvironmentVariableList
 **/
 EFI_STATUS
-EFIAPI
 SetEnvironmentVariables(
   IN CONST CHAR16 **Environment
   );
@@ -206,7 +203,6 @@ SetEnvironmentVariables(
   @param[in] List               The pointer to pointer to list.
 **/
 VOID
-EFIAPI
 FreeEnvironmentVariableList(
   IN LIST_ENTRY *List
   );
diff --git a/ShellPkg/Application/Shell/ShellManParser.c b/ShellPkg/Application/Shell/ShellManParser.c
index 948759fe46..7a290e16f6 100644
--- a/ShellPkg/Application/Shell/ShellManParser.c
+++ b/ShellPkg/Application/Shell/ShellManParser.c
@@ -63,7 +63,6 @@ SHELL_MAN_HII_VENDOR_DEVICE_PATH  mShellManHiiDevicePath = {
 
 **/
 CHAR16
-EFIAPI 
 InternalShellCharToUpper (
   IN CHAR16  Char
   );
@@ -79,7 +78,6 @@ InternalShellCharToUpper (
   @return                          the new filename with .efi as the extension.
 **/
 CHAR16 *
-EFIAPI
 GetExecuatableFileName (
   IN CONST CHAR16    *NameString
   )
@@ -132,7 +130,6 @@ GetExecuatableFileName (
   @return the new filename with .man as the extension.
 **/
 CHAR16 *
-EFIAPI
 GetManFileName(
   IN CONST CHAR16 *ManFileName
   )
@@ -179,7 +176,6 @@ GetManFileName(
   @retval EFI_NOT_FOUND         The file was not found.
 **/
 EFI_STATUS
-EFIAPI
 SearchPathForFile(
   IN CONST CHAR16             *FileName,
   OUT SHELL_FILE_HANDLE       *Handle
@@ -227,7 +223,6 @@ SearchPathForFile(
                                 an alloceted buffer.
 **/
 EFI_STATUS
-EFIAPI
 ManBufferFindSections(
   IN CONST CHAR16 *Buffer,
   IN CONST CHAR16 *Sections,
@@ -361,7 +356,6 @@ ManBufferFindSections(
                                 an alloceted buffer.
 **/
 EFI_STATUS
-EFIAPI
 ManFileFindSections(
   IN SHELL_FILE_HANDLE  Handle,
   IN CONST CHAR16       *Sections,
@@ -475,7 +469,6 @@ ManFileFindSections(
                                 an alloceted buffer.
 **/
 EFI_STATUS
-EFIAPI
 ManBufferFindTitleSection(
   IN CHAR16         **Buffer,
   IN CONST CHAR16   *Command,
@@ -712,7 +705,6 @@ IsTitleHeader(
                                 an allocated buffer if requested.
 **/
 EFI_STATUS
-EFIAPI
 ManFileFindTitleSection(
   IN SHELL_FILE_HANDLE  Handle,
   IN CONST CHAR16       *Command,
@@ -805,7 +797,6 @@ ManFileFindTitleSection(
   @retval EFI_NOT_FOUND         There is no help text available for Command.
 **/
 EFI_STATUS
-EFIAPI
 ProcessManFile(
   IN CONST CHAR16 *ManFileName,
   IN CONST CHAR16 *Command,
diff --git a/ShellPkg/Application/Shell/ShellManParser.h b/ShellPkg/Application/Shell/ShellManParser.h
index 3807eec9b2..bb530a3fcf 100644
--- a/ShellPkg/Application/Shell/ShellManParser.h
+++ b/ShellPkg/Application/Shell/ShellManParser.h
@@ -45,7 +45,6 @@
   @retval EFI_NOT_FOUND         There is no help text available for Command.
 **/
 EFI_STATUS
-EFIAPI
 ProcessManFile(
   IN CONST CHAR16 *ManFileName,
   IN CONST CHAR16 *Command,
@@ -73,7 +72,6 @@ ProcessManFile(
                                 an alloceted buffer.
 **/
 EFI_STATUS
-EFIAPI
 ManFileFindSections(
   IN SHELL_FILE_HANDLE  Handle,
   IN CONST CHAR16       *Sections,
diff --git a/ShellPkg/Application/Shell/ShellParametersProtocol.c b/ShellPkg/Application/Shell/ShellParametersProtocol.c
index 58156a21bd..499915521a 100644
--- a/ShellPkg/Application/Shell/ShellParametersProtocol.c
+++ b/ShellPkg/Application/Shell/ShellParametersProtocol.c
@@ -26,7 +26,6 @@ BOOLEAN AsciiRedirection = FALSE;
   @param[in] String        the string to parse
 **/
 CONST CHAR16*
-EFIAPI
 FindEndOfParameter(
   IN CONST CHAR16 *String
   )
@@ -86,7 +85,6 @@ FindEndOfParameter(
   @return   EFI_NOT_FOUND         A closing " could not be found on the specified string
 **/
 EFI_STATUS
-EFIAPI
 GetNextParameter(
   IN OUT CHAR16   **Walker,
   IN OUT CHAR16   **TempParameter,
@@ -196,7 +194,6 @@ DEBUG_CODE_END();
   @return EFI_OUT_OF_RESOURCES  a memory allocation failed.
 **/
 EFI_STATUS
-EFIAPI
 ParseCommandLineToArgs(
   IN CONST CHAR16 *CommandLine,
   IN BOOLEAN      StripQuotation,
@@ -296,7 +293,6 @@ Done:
   @sa ParseCommandLineToArgs
 **/
 EFI_STATUS
-EFIAPI
 CreatePopulateInstallShellParametersProtocol (
   IN OUT EFI_SHELL_PARAMETERS_PROTOCOL  **NewShellParameters,
   IN OUT BOOLEAN                        *RootShellInstance
@@ -438,7 +434,6 @@ CreatePopulateInstallShellParametersProtocol (
   @sa UninstallProtocolInterface
 **/
 EFI_STATUS
-EFIAPI
 CleanUpShellParametersProtocol (
   IN OUT EFI_SHELL_PARAMETERS_PROTOCOL  *NewShellParameters
   )
@@ -485,7 +480,6 @@ CleanUpShellParametersProtocol (
   @return An error upon failure.
 **/
 EFI_STATUS
-EFIAPI
 IsUnicodeFile(
   IN CONST CHAR16 *FileName
   )
@@ -520,7 +514,6 @@ IsUnicodeFile(
   @param[in, out] TheString  A pointer to the string to update.
 **/
 VOID
-EFIAPI
 StripQuotes (
   IN OUT CHAR16 *TheString
   )
@@ -572,7 +565,6 @@ CalculateEfiHdrCrc (
   @return       The modified FileName.
 **/
 CHAR16*
-EFIAPI
 FixFileName (
   IN CHAR16 *FileName
   )
@@ -615,7 +607,6 @@ FixFileName (
   @return       The modified FileName.
 **/
 CHAR16*
-EFIAPI
 FixVarName (
   IN CHAR16 *FileName
   )
@@ -644,7 +635,6 @@ FixVarName (
   @retval EFI_SUCCESS   The unicode file tag has been moved successfully.
 **/
 EFI_STATUS
-EFIAPI
 RemoveFileTag(
   IN SHELL_FILE_HANDLE *Handle
   )
@@ -708,7 +698,6 @@ WriteFileTag (
   @retval   EFI_OUT_OF_RESOURCES        A memory allocation failed.
 **/
 EFI_STATUS
-EFIAPI
 UpdateStdInStdOutStdErr(
   IN OUT EFI_SHELL_PARAMETERS_PROTOCOL  *ShellParameters,
   IN CHAR16                             *NewCommandLine,
@@ -1308,7 +1297,6 @@ UpdateStdInStdOutStdErr(
   @param[in] SystemTableInfo           Pointer to old system table information.
 **/
 EFI_STATUS
-EFIAPI
 RestoreStdInStdOutStdErr (
   IN OUT EFI_SHELL_PARAMETERS_PROTOCOL  *ShellParameters,
   IN  SHELL_FILE_HANDLE                 *OldStdIn,
@@ -1385,7 +1373,6 @@ RestoreStdInStdOutStdErr (
   @retval   EFI_OUT_OF_RESOURCES        A memory allocation failed.
 **/
 EFI_STATUS
-EFIAPI
 UpdateArgcArgv(
   IN OUT EFI_SHELL_PARAMETERS_PROTOCOL  *ShellParameters,
   IN CONST CHAR16                       *NewCommandLine,
@@ -1427,7 +1414,6 @@ UpdateArgcArgv(
   @param[in] OldArgc                    pointer to old number of items in Argv list
 **/
 VOID
-EFIAPI
 RestoreArgcArgv(
   IN OUT EFI_SHELL_PARAMETERS_PROTOCOL  *ShellParameters,
   IN CHAR16                             ***OldArgv,
diff --git a/ShellPkg/Application/Shell/ShellParametersProtocol.h b/ShellPkg/Application/Shell/ShellParametersProtocol.h
index 926f36242c..61cabca2c2 100644
--- a/ShellPkg/Application/Shell/ShellParametersProtocol.h
+++ b/ShellPkg/Application/Shell/ShellParametersProtocol.h
@@ -43,7 +43,6 @@ typedef enum {
   @sa ParseCommandLineToArgs
 **/
 EFI_STATUS
-EFIAPI
 CreatePopulateInstallShellParametersProtocol (
   IN OUT EFI_SHELL_PARAMETERS_PROTOCOL  **NewShellParameters,
   IN OUT BOOLEAN                        *RootShellInstance
@@ -62,7 +61,6 @@ CreatePopulateInstallShellParametersProtocol (
   @sa UninstallProtocolInterface
 **/
 EFI_STATUS
-EFIAPI
 CleanUpShellParametersProtocol (
   IN OUT EFI_SHELL_PARAMETERS_PROTOCOL  *NewShellParameters
   );
@@ -82,7 +80,6 @@ CleanUpShellParametersProtocol (
   @retval   EFI_OUT_OF_RESOURCES        a memory allocation failed.
 **/
 EFI_STATUS
-EFIAPI
 UpdateArgcArgv(
   IN OUT EFI_SHELL_PARAMETERS_PROTOCOL  *ShellParameters,
   IN CONST CHAR16                       *NewCommandLine,
@@ -101,7 +98,6 @@ UpdateArgcArgv(
   @param[in] OldArgc                    pointer to old number of items in Argv list
 **/
 VOID
-EFIAPI
 RestoreArgcArgv(
   IN OUT EFI_SHELL_PARAMETERS_PROTOCOL  *ShellParameters,
   IN CHAR16                             ***OldArgv,
@@ -135,7 +131,6 @@ typedef struct {
   @retval   EFI_OUT_OF_RESOURCES        A memory allocation failed.
 **/
 EFI_STATUS
-EFIAPI
 UpdateStdInStdOutStdErr(
   IN OUT EFI_SHELL_PARAMETERS_PROTOCOL  *ShellParameters,
   IN CHAR16                             *NewCommandLine,
@@ -156,7 +151,6 @@ UpdateStdInStdOutStdErr(
   @param[in] SystemTableInfo           Pointer to old system table information.
 **/
 EFI_STATUS
-EFIAPI
 RestoreStdInStdOutStdErr (
   IN OUT EFI_SHELL_PARAMETERS_PROTOCOL  *ShellParameters,
   IN  SHELL_FILE_HANDLE                 *OldStdIn,
@@ -182,7 +176,6 @@ RestoreStdInStdOutStdErr (
   @return EFI_OUT_OF_RESOURCES  a memory allocation failed.
 **/
 EFI_STATUS
-EFIAPI
 ParseCommandLineToArgs(
   IN CONST CHAR16 *CommandLine,
   IN BOOLEAN      StripQuotation,
@@ -211,7 +204,6 @@ ParseCommandLineToArgs(
   @return   EFI_NOT_FOUND         A closing " could not be found on the specified string
 **/
 EFI_STATUS
-EFIAPI
 GetNextParameter(
   IN OUT CHAR16   **Walker,
   IN OUT CHAR16   **TempParameter,
diff --git a/ShellPkg/Application/Shell/ShellProtocol.c b/ShellPkg/Application/Shell/ShellProtocol.c
index fb7dd84e5a..2bc0646b45 100644
--- a/ShellPkg/Application/Shell/ShellProtocol.c
+++ b/ShellPkg/Application/Shell/ShellProtocol.c
@@ -50,7 +50,6 @@ EfiShellClose (
   @retval FALSE     gEfiBlockIoProtocolGuid was not found.
 **/
 BOOLEAN
-EFIAPI
 InternalShellProtocolIsBlockIoPresent(
   IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
   )
@@ -80,7 +79,6 @@ InternalShellProtocolIsBlockIoPresent(
   @retval FALSE     gEfiSimpleFileSystemProtocolGuid was not found.
 **/
 BOOLEAN
-EFIAPI
 InternalShellProtocolIsSimpleFileSystemPresent(
   IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
   )
@@ -113,7 +111,6 @@ InternalShellProtocolIsSimpleFileSystemPresent(
   @sa OpenProtocol
 **/
 EFI_STATUS
-EFIAPI
 InternalShellProtocolDebugPrintMessage (
   IN CONST CHAR16                   *Mapping,
   IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
@@ -951,7 +948,6 @@ EfiShellBatchIsActive (
   @retval other                   an error ocurred.
 **/
 EFI_STATUS
-EFIAPI
 InternalOpenFileDevicePath(
   IN OUT EFI_DEVICE_PATH_PROTOCOL *DevicePath,
   OUT SHELL_FILE_HANDLE           *FileHandle,
@@ -1183,7 +1179,7 @@ EfiShellCreateFile(
   @retval EFI_ACCESS_DENIED       Guid already is assigned a name.
 **/
 EFI_STATUS
-EFIAPI 
+EFIAPI
 EfiShellRegisterGuidName(
   IN CONST EFI_GUID *Guid,
   IN CONST CHAR16   *GuidName
@@ -1430,7 +1426,6 @@ EfiShellEnablePageBreak (
   @retval EFI_UNSUPPORTED   Nested shell invocations are not allowed.
 **/
 EFI_STATUS
-EFIAPI
 InternalShellExecuteDevicePath(
   IN CONST EFI_HANDLE               *ParentImageHandle,
   IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
@@ -1639,7 +1634,6 @@ FreeAlloc:
   @retval EFI_UNSUPPORTED   Nested shell invocations are not allowed.
 **/
 EFI_STATUS
-EFIAPI
 InternalShellExecute(
   IN CONST CHAR16                   *CommandLine OPTIONAL,
   IN CONST CHAR16                   **Environment OPTIONAL,
@@ -1683,7 +1677,6 @@ InternalShellExecute(
 **/
 STATIC
 BOOLEAN
-EFIAPI
 NestingEnabled(
 )
 {
@@ -1822,7 +1815,6 @@ EfiShellExecute(
   @param FileListNode     pointer to the list node to free
 **/
 VOID
-EFIAPI
 InternalFreeShellFileInfoNode(
   IN EFI_SHELL_FILE_INFO *FileListNode
   )
@@ -1950,7 +1942,6 @@ typedef struct {
   @return != NULL     a pointer to the new node
 **/
 EFI_SHELL_FILE_INFO*
-EFIAPI
 InternalDuplicateShellFileInfo(
   IN       EFI_SHELL_FILE_INFO *Node,
   IN BOOLEAN                   Save
@@ -2003,7 +1994,6 @@ InternalDuplicateShellFileInfo(
   @return                     a pointer to the newly allocated structure.
 **/
 EFI_SHELL_FILE_INFO *
-EFIAPI
 CreateAndPopulateShellFileInfo(
   IN CONST CHAR16 *BasePath,
   IN CONST EFI_STATUS Status,
@@ -2201,7 +2191,7 @@ EfiShellFindFilesInDir(
   @retval EFI_NOT_FOUND           GuidName is not a known GUID Name.
 **/
 EFI_STATUS
-EFIAPI 
+EFIAPI
 EfiShellGetGuidFromName(
   IN  CONST CHAR16   *GuidName,
   OUT       EFI_GUID *Guid
@@ -2241,7 +2231,7 @@ EfiShellGetGuidFromName(
   @retval EFI_NOT_FOUND           Guid is not assigned a name.
 **/
 EFI_STATUS
-EFIAPI 
+EFIAPI
 EfiShellGetGuidName(
   IN  CONST EFI_GUID *Guid,
   OUT CONST CHAR16   **GuidName
@@ -2274,7 +2264,6 @@ EfiShellGetGuidName(
   @retval EFI_OUT_OF_RESOURCES
 **/
 EFI_STATUS
-EFIAPI
 UpdateFileName(
   IN CONST CHAR16 *BasePath,
   IN OUT CHAR16   **Path
@@ -2335,7 +2324,6 @@ UpdateFileName(
   @retval EFI_OUT_OF_RESOURCES  a memory allocation failed
 **/
 EFI_STATUS
-EFIAPI
 ShellSearchHandle(
   IN     CONST CHAR16                         *FilePattern,
   IN           EFI_UNICODE_COLLATION_PROTOCOL *UnicodeCollation,
@@ -2726,7 +2714,7 @@ EfiShellOpenFileList(
                                 pointer does not need to be freed by the caller.
 **/
 CONST CHAR16 *
-EFIAPI 
+EFIAPI
 EfiShellGetEnvEx(
   IN  CONST CHAR16 *Name,
   OUT       UINT32 *Attributes OPTIONAL
@@ -2863,7 +2851,6 @@ EfiShellGetEnv(
   @retval EFI_SUCCESS           The environment variable was successfully updated.
 **/
 EFI_STATUS
-EFIAPI
 InternalEfiShellSetEnv(
   IN CONST CHAR16 *Name,
   IN CONST CHAR16 *Value,
@@ -3297,7 +3284,6 @@ EfiShellIsRootShell(
   @return !NULL   a list of all alias'
 **/
 CHAR16 *
-EFIAPI
 InternalEfiShellGetListAlias(
   )
 {
@@ -3469,7 +3455,6 @@ EfiShellGetAlias(
   @retval EFI_NOT_FOUND         the Alias intended to be deleted was not found
 **/
 EFI_STATUS
-EFIAPI
 InternalSetAlias(
   IN CONST CHAR16 *Command,
   IN CONST CHAR16 *Alias,
@@ -3633,7 +3618,6 @@ EFI_SHELL_PROTOCOL         mShellProtocol = {
   @return                 An error from LocateHandle, CreateEvent, or other core function.
 **/
 EFI_STATUS
-EFIAPI
 CreatePopulateInstallShellProtocol (
   IN OUT EFI_SHELL_PROTOCOL  **NewShell
   )
@@ -3873,7 +3857,6 @@ NotificationFunction(
   @retval EFI_OUT_OF_RESOURCES  There is not enough mnemory available.
 **/
 EFI_STATUS
-EFIAPI
 InernalEfiShellStartMonitor(
   VOID
   )
diff --git a/ShellPkg/Application/Shell/ShellProtocol.h b/ShellPkg/Application/Shell/ShellProtocol.h
index 4f701cb749..755a402c98 100644
--- a/ShellPkg/Application/Shell/ShellProtocol.h
+++ b/ShellPkg/Application/Shell/ShellProtocol.h
@@ -43,7 +43,6 @@ typedef struct {
   @return                 An error from LocateHandle, CreateEvent, or other core function.
 **/
 EFI_STATUS
-EFIAPI
 CreatePopulateInstallShellProtocol (
   IN OUT EFI_SHELL_PROTOCOL  **NewShell
   );
@@ -294,7 +293,6 @@ EfiShellBatchIsActive (
   @retval other                   an error ocurred.
 **/
 EFI_STATUS
-EFIAPI
 InternalOpenFileDevicePath(
   IN OUT EFI_DEVICE_PATH_PROTOCOL *DevicePath2,
   OUT SHELL_FILE_HANDLE             *FileHandle,
@@ -464,7 +462,6 @@ EfiShellEnablePageBreak (
   @retval EFI_UNSUPPORTED   Nested shell invocations are not allowed.
 **/
 EFI_STATUS
-EFIAPI
 InternalShellExecuteDevicePath(
   IN CONST EFI_HANDLE               *ParentImageHandle,
   IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
@@ -522,7 +519,6 @@ EfiShellExecute(
   @param FileListNode     pointer to the list node to free
 **/
 VOID
-EFIAPI
 FreeShellFileInfoNode(
   IN EFI_SHELL_FILE_INFO *FileListNode
   );
@@ -573,7 +569,6 @@ EfiShellRemoveDupInFileList(
 
 **/
 EFI_SHELL_FILE_INFO *
-EFIAPI
 CreateAndPopulateShellFileInfo(
   IN CONST CHAR16 *BasePath,
   IN CONST EFI_STATUS Status,
@@ -856,7 +851,6 @@ EfiShellGetAlias(
   @retval EFI_NOT_FOUND         the Alias intended to be deleted was not found
 **/
 EFI_STATUS
-EFIAPI
 InternalSetAlias(
   IN CONST CHAR16 *Command,
   IN CONST CHAR16 *Alias OPTIONAL,
@@ -901,7 +895,6 @@ EfiShellSetAlias(
   @param FileListNode     pointer to the list node to free
 **/
 VOID
-EFIAPI
 InternalFreeShellFileInfoNode(
   IN EFI_SHELL_FILE_INFO *FileListNode
   );
@@ -917,7 +910,6 @@ InternalFreeShellFileInfoNode(
   @retval EFI_SUCCESS           The environment variable was successfully updated.
 **/
 EFI_STATUS
-EFIAPI
 InternalEfiShellSetEnv(
   IN CONST CHAR16 *Name,
   IN CONST CHAR16 *Value,
@@ -932,7 +924,6 @@ InternalEfiShellSetEnv(
   @retval EFI_OUT_OF_RESOURCES  There is not enough mnemory available.
 **/
 EFI_STATUS
-EFIAPI
 InernalEfiShellStartMonitor(
   VOID
   );