diff --git a/internal/filedesc/desc.go b/internal/filedesc/desc.go
index 72a45e2..8185758 100644
--- a/internal/filedesc/desc.go
+++ b/internal/filedesc/desc.go
@@ -180,14 +180,14 @@
 		L2 *MessageL2 // protected by fileDesc.once
 	}
 	MessageL1 struct {
-		Enums      Enums
-		Messages   Messages
-		Extensions Extensions
+		Enums        Enums
+		Messages     Messages
+		Extensions   Extensions
+		IsMapEntry   bool // promoted from google.protobuf.MessageOptions
+		IsMessageSet bool // promoted from google.protobuf.MessageOptions
 	}
 	MessageL2 struct {
 		Options               func() pref.ProtoMessage
-		IsMapEntry            bool // promoted from google.protobuf.MessageOptions
-		IsMessageSet          bool // promoted from google.protobuf.MessageOptions
 		Fields                Fields
 		Oneofs                Oneofs
 		ReservedNames         Names
@@ -234,7 +234,7 @@
 	}
 	return descopts.Message
 }
-func (md *Message) IsMapEntry() bool                   { return md.lazyInit().IsMapEntry }
+func (md *Message) IsMapEntry() bool                   { return md.L1.IsMapEntry }
 func (md *Message) Fields() pref.FieldDescriptors      { return &md.lazyInit().Fields }
 func (md *Message) Oneofs() pref.OneofDescriptors      { return &md.lazyInit().Oneofs }
 func (md *Message) ReservedNames() pref.Names          { return &md.lazyInit().ReservedNames }
@@ -263,7 +263,7 @@
 // WARNING: This method is exempt from the compatibility promise and may be
 // removed in the future without warning.
 func (md *Message) IsMessageSet() bool {
-	return md.lazyInit().IsMessageSet
+	return md.L1.IsMessageSet
 }
 
 func (fd *Field) Options() pref.ProtoMessage {
diff --git a/internal/filedesc/desc_init.go b/internal/filedesc/desc_init.go
index 1b6daf0..249021f 100644
--- a/internal/filedesc/desc_init.go
+++ b/internal/filedesc/desc_init.go
@@ -314,6 +314,8 @@
 					posExtensions = len(b0) - len(b) - n - m
 				}
 				numExtensions++
+			case fieldnum.DescriptorProto_Options:
+				md.unmarshalSeedOptions(v)
 			}
 			prevField = num
 		default:
@@ -364,6 +366,27 @@
 	}
 }
 
+func (md *Message) unmarshalSeedOptions(b []byte) {
+	for len(b) > 0 {
+		num, typ, n := wire.ConsumeTag(b)
+		b = b[n:]
+		switch typ {
+		case wire.VarintType:
+			v, m := wire.ConsumeVarint(b)
+			b = b[m:]
+			switch num {
+			case fieldnum.MessageOptions_MapEntry:
+				md.L1.IsMapEntry = wire.DecodeBool(v)
+			case fieldnum.MessageOptions_MessageSetWireFormat:
+				md.L1.IsMessageSet = wire.DecodeBool(v)
+			}
+		default:
+			m := wire.ConsumeFieldValue(num, typ, b)
+			b = b[m:]
+		}
+	}
+}
+
 func (xd *Extension) unmarshalSeed(b []byte, sb *strs.Builder, pf *File, pd pref.Descriptor, i int) {
 	xd.L0.ParentFile = pf
 	xd.L0.Parent = pd
diff --git a/internal/filedesc/desc_lazy.go b/internal/filedesc/desc_lazy.go
index 86720a0..309d739 100644
--- a/internal/filedesc/desc_lazy.go
+++ b/internal/filedesc/desc_lazy.go
@@ -348,9 +348,9 @@
 			b = b[m:]
 			switch num {
 			case fieldnum.MessageOptions_MapEntry:
-				md.L2.IsMapEntry = wire.DecodeBool(v)
+				md.L1.IsMapEntry = wire.DecodeBool(v)
 			case fieldnum.MessageOptions_MessageSetWireFormat:
-				md.L2.IsMessageSet = wire.DecodeBool(v)
+				md.L1.IsMessageSet = wire.DecodeBool(v)
 			}
 		default:
 			m := wire.ConsumeFieldValue(num, typ, b)
diff --git a/internal/impl/legacy_message.go b/internal/impl/legacy_message.go
index dbc99ed..e078045 100644
--- a/internal/impl/legacy_message.go
+++ b/internal/impl/legacy_message.go
@@ -297,7 +297,7 @@
 				md2.L0.Parent = md
 				md2.L0.Index = n
 
-				md2.L2.IsMapEntry = true
+				md2.L1.IsMapEntry = true
 				md2.L2.Options = func() pref.ProtoMessage {
 					opts := descopts.Message.ProtoReflect().New()
 					opts.Set(opts.Descriptor().Fields().ByName("map_entry"), protoreflect.ValueOfBool(true))
diff --git a/reflect/protodesc/desc_init.go b/reflect/protodesc/desc_init.go
index 2fe19b0..6f689b1 100644
--- a/reflect/protodesc/desc_init.go
+++ b/reflect/protodesc/desc_init.go
@@ -70,8 +70,8 @@
 		if opts := md.GetOptions(); opts != nil {
 			opts = clone(opts).(*descriptorpb.MessageOptions)
 			m.L2.Options = func() protoreflect.ProtoMessage { return opts }
-			m.L2.IsMapEntry = opts.GetMapEntry()
-			m.L2.IsMessageSet = opts.GetMessageSetWireFormat()
+			m.L1.IsMapEntry = opts.GetMapEntry()
+			m.L1.IsMessageSet = opts.GetMessageSetWireFormat()
 		}
 		for _, s := range md.GetReservedName() {
 			m.L2.ReservedNames.List = append(m.L2.ReservedNames.List, protoreflect.Name(s))