diff --git a/OvmfPkg/Tcg/TdTcg2Dxe/TdTcg2Dxe.c b/OvmfPkg/Tcg/TdTcg2Dxe/TdTcg2Dxe.c
index 0a23bff5a1..6d2de0e838 100644
--- a/OvmfPkg/Tcg/TdTcg2Dxe/TdTcg2Dxe.c
+++ b/OvmfPkg/Tcg/TdTcg2Dxe/TdTcg2Dxe.c
@@ -2160,11 +2160,17 @@ OnReadyToBoot (
 
     //
     // 2. Draw a line between pre-boot env and entering post-boot env.
-    // PCR[7] (is RTMR[0]) is already done.
     //
-    Status = MeasureSeparatorEvent (1);
+    // According to UEFI Spec 2.10 Section 38.4.1 the mapping between MrIndex and Intel
+    // TDX Measurement Register is:
+    //    MrIndex 0   <--> MRTD
+    //    MrIndex 1-3 <--> RTMR[0-2]
+    // RTMR[0] (i.e. MrIndex 1) is already done. So SepartorEvent shall be extended to
+    // RTMR[1] (i.e. MrIndex 2) as well.
+    //
+    Status = MeasureSeparatorEvent (CC_MR_INDEX_2_RTMR1);
     if (EFI_ERROR (Status)) {
-      DEBUG ((DEBUG_ERROR, "Separator Event not Measured. Error!\n"));
+      DEBUG ((DEBUG_ERROR, "Separator Event not Measured to RTMR[1]. Error!\n"));
     }
 
     //