diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
index 1d09bb879d..5e155f0705 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
@@ -2536,7 +2536,16 @@ LegacyBiosInstallRom (
   //
   // The ROM could have updated it's size so we need to read again.
   //
-  *RuntimeImageLength = ((EFI_LEGACY_EXPANSION_ROM_HEADER *) (RuntimeAddress))->Size512 * 512;
+  if ((((EFI_LEGACY_EXPANSION_ROM_HEADER *) RuntimeAddress)->Signature != PCI_EXPANSION_ROM_HEADER_SIGNATURE) &&
+      (((EFI_LEGACY_EXPANSION_ROM_HEADER *) InitAddress)->Size512 == 0)) {
+    //
+    // The INIT function didn't copy the RUNTIME code to RuntimeAddress
+    //
+    *RuntimeImageLength = 0;
+  } else {
+    *RuntimeImageLength = ((EFI_LEGACY_EXPANSION_ROM_HEADER *) RuntimeAddress)->Size512 * 512;
+  }
+
   DEBUG ((EFI_D_INFO, " fsize = %x\n", *RuntimeImageLength));
 
   //