diff --git a/src/coreclr/src/inc/corinfo.h b/src/coreclr/src/inc/corinfo.h
index 2c8c1260b73925..159b8ad92a6401 100644
--- a/src/coreclr/src/inc/corinfo.h
+++ b/src/coreclr/src/inc/corinfo.h
@@ -822,7 +822,7 @@ enum CorInfoFlag
     CORINFO_FLG_ARRAY                 = 0x00080000, // class is an array class (initialized differently)
     CORINFO_FLG_OVERLAPPING_FIELDS    = 0x00100000, // struct or class has fields that overlap (aka union)
     CORINFO_FLG_INTERFACE             = 0x00200000, // it is an interface
-    // unused                         = 0x00400000,
+    CORINFO_FLG_DONT_PROMOTE          = 0x00400000, // don't try to promote fields (used for types outside of AOT compilation version bubble)
     CORINFO_FLG_CUSTOMLAYOUT          = 0x00800000, // does this struct have custom layout?
     CORINFO_FLG_CONTAINS_GC_PTR       = 0x01000000, // does the class contain a gc ptr ?
     CORINFO_FLG_DELEGATE              = 0x02000000, // is this a subclass of delegate or multicast delegate ?
diff --git a/src/coreclr/src/jit/compiler.hpp b/src/coreclr/src/jit/compiler.hpp
index f3e590a7303a45..4dc68abbc476a9 100644
--- a/src/coreclr/src/jit/compiler.hpp
+++ b/src/coreclr/src/jit/compiler.hpp
@@ -4670,6 +4670,11 @@ inline static bool StructHasCustomLayout(DWORD attribs)
     return ((attribs & CORINFO_FLG_CUSTOMLAYOUT) != 0);
 }
 
+inline static bool StructHasNoPromotionFlagSet(DWORD attribs)
+{
+    return ((attribs & CORINFO_FLG_DONT_PROMOTE) != 0);
+}
+
 /*****************************************************************************
  * This node should not be referenced by anyone now. Set its values to garbage
  * to catch extra references
diff --git a/src/coreclr/src/jit/lclvars.cpp b/src/coreclr/src/jit/lclvars.cpp
index 608b4410cd9421..4788b6c84a6c76 100644
--- a/src/coreclr/src/jit/lclvars.cpp
+++ b/src/coreclr/src/jit/lclvars.cpp
@@ -1686,6 +1686,13 @@ bool Compiler::StructPromotionHelper::CanPromoteStructType(CORINFO_CLASS_HANDLE
     structPromotionInfo.fieldCnt = (unsigned char)fieldCnt;
     DWORD typeFlags              = compHandle->getClassAttribs(typeHnd);
 
+    if (StructHasNoPromotionFlagSet(typeFlags))
+    {
+        // In AOT ReadyToRun compilation, don't try to promote fields of types
+        // outside of the current version bubble.
+        return false;
+    }
+
     bool overlappingFields = StructHasOverlappingFields(typeFlags);
     if (overlappingFields)
     {
diff --git a/src/coreclr/src/tools/Common/JitInterface/CorInfoImpl.cs b/src/coreclr/src/tools/Common/JitInterface/CorInfoImpl.cs
index 205304c49a36b9..fef6e6e5eb5ed7 100644
--- a/src/coreclr/src/tools/Common/JitInterface/CorInfoImpl.cs
+++ b/src/coreclr/src/tools/Common/JitInterface/CorInfoImpl.cs
@@ -1070,7 +1070,7 @@ private void resolveToken(ref CORINFO_RESOLVED_TOKEN pResolvedToken)
 
 #if READYTORUN
             TypeDesc owningType = methodIL.OwningMethod.GetTypicalMethodDefinition().OwningType;
-            bool recordToken = _compilation.NodeFactory.CompilationModuleGroup.VersionsWithType(owningType) && owningType is EcmaType;
+            bool recordToken = _compilation.CompilationModuleGroup.VersionsWithType(owningType) && owningType is EcmaType;
 #endif
 
             if (result is MethodDesc)
@@ -1220,7 +1220,9 @@ private CorInfoType asCorInfoType(CORINFO_CLASS_STRUCT_* cls)
         private byte* getClassName(CORINFO_CLASS_STRUCT_* cls)
         {
             var type = HandleToObject(cls);
-            return (byte*)GetPin(StringToUTF8(type.ToString()));
+            StringBuilder nameBuilder = new StringBuilder();
+            TypeString.Instance.AppendName(nameBuilder, type);
+            return (byte*)GetPin(StringToUTF8(nameBuilder.ToString()));
         }
 
         private byte* getClassNameFromMetadata(CORINFO_CLASS_STRUCT_* cls, byte** namespaceName)
@@ -1357,6 +1359,15 @@ private uint getClassAttribsInternal(TypeDesc type)
                     result |= CorInfoFlag.CORINFO_FLG_ABSTRACT;
             }
 
+#if READYTORUN
+            if (!_compilation.CompilationModuleGroup.VersionsWithType(type))
+            {
+                // Prevent the JIT from drilling into types outside of the current versioning bubble
+                result |= CorInfoFlag.CORINFO_FLG_DONT_PROMOTE;
+                result &= ~CorInfoFlag.CORINFO_FLG_BEFOREFIELDINIT;
+            }
+#endif
+
             return (uint)result;
         }
 
diff --git a/src/coreclr/src/tools/Common/JitInterface/CorInfoTypes.cs b/src/coreclr/src/tools/Common/JitInterface/CorInfoTypes.cs
index 990c2713de72c9..2313d5e58b7a00 100644
--- a/src/coreclr/src/tools/Common/JitInterface/CorInfoTypes.cs
+++ b/src/coreclr/src/tools/Common/JitInterface/CorInfoTypes.cs
@@ -634,7 +634,7 @@ public enum CorInfoFlag : uint
         CORINFO_FLG_ARRAY = 0x00080000, // class is an array class (initialized differently)
         CORINFO_FLG_OVERLAPPING_FIELDS = 0x00100000, // struct or class has fields that overlap (aka union)
         CORINFO_FLG_INTERFACE = 0x00200000, // it is an interface
-        // CORINFO_FLG_UNUSED = 0x00400000,
+        CORINFO_FLG_DONT_PROMOTE = 0x00400000, // don't try to promote fieds of types outside of AOT compilation version bubble
         CORINFO_FLG_CUSTOMLAYOUT = 0x00800000, // does this struct have custom layout?
         CORINFO_FLG_CONTAINS_GC_PTR = 0x01000000, // does the class contain a gc ptr ?
         CORINFO_FLG_DELEGATE = 0x02000000, // is this a subclass of delegate or multicast delegate ?