diff --git a/lib/libefivar/efivar-dp-format.c b/lib/libefivar/efivar-dp-format.c
index e2a5e666ce7..0062216ac30 100644
--- a/lib/libefivar/efivar-dp-format.c
+++ b/lib/libefivar/efivar-dp-format.c
@@ -539,13 +539,22 @@ DevPathToTextAcpiEx (
     //
     // use AcpiExp()
     //
-    UefiDevicePathLibCatPrint (
-      Str,
-      "AcpiExp(%s,%s,%s)",
-      HIDText,
-      CIDText,
-      UIDStr
-      );
+    if (AcpiEx->CID == 0) {
+      UefiDevicePathLibCatPrint (
+         Str,
+         "AcpiExp(%s,0,%s)",
+         HIDText,
+         UIDStr
+        );
+    } else {
+      UefiDevicePathLibCatPrint (
+        Str,
+        "AcpiExp(%s,%s,%s)",
+        HIDText,
+        CIDText,
+        UIDStr
+        );
+    }
   } else {
     if (AllowShortcuts) {
       //
diff --git a/lib/libefivar/efivar-dp-parse.c b/lib/libefivar/efivar-dp-parse.c
index a4c7cff57c0..c6ea7bc00a5 100644
--- a/lib/libefivar/efivar-dp-parse.c
+++ b/lib/libefivar/efivar-dp-parse.c
@@ -1014,7 +1014,16 @@ DevPathFromTextAcpiExp (
                                                   );
 
   AcpiEx->HID = EisaIdFromText (HIDStr);
-  AcpiEx->CID = EisaIdFromText (CIDStr);
+  //
+  // According to UEFI spec, the CID parameter is optional and has a default value of 0.
+  // So when the CID parameter is not specified or specified as 0 in the text device node.
+  // Set the CID to 0 in the ACPI extension device path structure.
+  //
+  if (*CIDStr == '\0' || *CIDStr == '0') {
+    AcpiEx->CID = 0;
+  } else {
+    AcpiEx->CID = EisaIdFromText (CIDStr);
+  }
   AcpiEx->UID = 0;
 
   AsciiStr = (CHAR8 *) ((UINT8 *)AcpiEx + sizeof (ACPI_EXTENDED_HID_DEVICE_PATH));