diff --git a/SecurityPkg/Tcg/Opal/OpalPasswordDxe/OpalHii.c b/SecurityPkg/Tcg/Opal/OpalPasswordDxe/OpalHii.c
index 9a44c5697e..ee73697d80 100644
--- a/SecurityPkg/Tcg/Opal/OpalPasswordDxe/OpalHii.c
+++ b/SecurityPkg/Tcg/Opal/OpalPasswordDxe/OpalHii.c
@@ -595,12 +595,15 @@ HiiPsidRevert(
   OPAL_DISK                     *OpalDisk;
   TCG_RESULT                    Ret;
   OPAL_SESSION                  Session;
+  UINT8                         TmpBuf[PSID_CHARACTER_STRING_END_LENGTH];
 
   Ret = TcgResultFailure;
 
   OpalHiiGetBrowserData();
 
-  UnicodeStrToAsciiStrS (gHiiConfiguration.Psid, (CHAR8*)Psid.Psid, PSID_CHARACTER_LENGTH);
+  ZeroMem (TmpBuf, sizeof (TmpBuf));
+  UnicodeStrToAsciiStrS (gHiiConfiguration.Psid, (CHAR8*)TmpBuf, PSID_CHARACTER_STRING_END_LENGTH);
+  CopyMem (Psid.Psid, TmpBuf, PSID_CHARACTER_LENGTH);
 
   OpalDisk = HiiGetOpalDiskCB (gHiiConfiguration.SelectedDiskIndex);
   if (OpalDisk != NULL) {
diff --git a/SecurityPkg/Tcg/Opal/OpalPasswordDxe/OpalHiiFormValues.h b/SecurityPkg/Tcg/Opal/OpalPasswordDxe/OpalHiiFormValues.h
index 138bcb8935..88cf9f5b59 100644
--- a/SecurityPkg/Tcg/Opal/OpalPasswordDxe/OpalHiiFormValues.h
+++ b/SecurityPkg/Tcg/Opal/OpalPasswordDxe/OpalHiiFormValues.h
@@ -21,6 +21,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
 // PSID Length
 #define PSID_CHARACTER_LENGTH                              0x20
+#define PSID_CHARACTER_STRING_END_LENGTH                   0x21
 
 // ID's for various forms that will be used by HII
 #define FORMID_VALUE_MAIN_MENU                             0x01
@@ -38,7 +39,7 @@ typedef struct {
     UINT8   KeepUserData;
     UINT16  AvailableFields;
     UINT16  Password[MAX_PASSWORD_CHARACTER_LENGTH];
-    UINT16  Psid[PSID_CHARACTER_LENGTH];
+    UINT16  Psid[PSID_CHARACTER_STRING_END_LENGTH];
     UINT8   EnableBlockSid;
 } OPAL_HII_CONFIGURATION;
 #pragma pack()