diff --git a/rts/motoko-rts/src/persistence.rs b/rts/motoko-rts/src/persistence.rs
index f7428393ab5..eb45fa8672d 100644
--- a/rts/motoko-rts/src/persistence.rs
+++ b/rts/motoko-rts/src/persistence.rs
@@ -222,7 +222,6 @@ pub unsafe fn assign_stable_type<M: Memory>(
     (*metadata).stable_type.assign(mem, &new_type);
 }
 
-
 pub(crate) unsafe fn stable_type_descriptor() -> &'static mut TypeDescriptor {
     let metadata = PersistentMetadata::get();
     &mut (*metadata).stable_type
diff --git a/src/codegen/compile_classical.ml b/src/codegen/compile_classical.ml
index a16282ca4db..1061c7d344a 100644
--- a/src/codegen/compile_classical.ml
+++ b/src/codegen/compile_classical.ml
@@ -11616,6 +11616,15 @@ and compile_prim_invocation (env : E.t) ae p es at =
     SR.Vanilla,
     StableMem.get_mem_size env ^^ BigNum.from_word64 env
 
+  | OtherPrim "rts_in_install", [] -> (* classical specific *)
+    assert (not !Flags.enhanced_orthogonal_persistence);
+    SR.Vanilla,
+    StableMem.stable64_size env ^^
+    G.i (Test (Wasm_exts.Values.I64 I64Op.Eqz)) ^^
+    G.if1 I32Type
+      (Bool.lit true)
+      (Bool.lit false)
+
   (* Regions *)
 
   | OtherPrim "regionNew", [] ->
diff --git a/src/codegen/compile_enhanced.ml b/src/codegen/compile_enhanced.ml
index 36d6990e487..b6addc1291b 100644
--- a/src/codegen/compile_enhanced.ml
+++ b/src/codegen/compile_enhanced.ml
@@ -8757,6 +8757,7 @@ module EnhancedOrthogonalPersistence = struct
 
   let initialize env actor_type =
     register_stable_type env actor_type
+
 end (* EnhancedOrthogonalPersistence *)
 
 (* As fallback when doing persistent memory layout changes. *)
@@ -11684,6 +11685,15 @@ and compile_prim_invocation (env : E.t) ae p es at =
     SR.Vanilla,
     StableMem.get_mem_size env ^^ BigNum.from_word64 env
 
+  | OtherPrim "rts_in_install", [] -> (* EOP specific *)
+    assert (!Flags.enhanced_orthogonal_persistence);
+    SR.Vanilla,
+    EnhancedOrthogonalPersistence.load_stable_actor env ^^
+    compile_test I64Op.Eqz ^^
+    E.if1 I64Type
+      (Bool.lit true)
+      (Bool.lit false)
+
   (* Regions *)
 
   | OtherPrim "regionNew", [] ->
@@ -12258,9 +12268,11 @@ and compile_prim_invocation (env : E.t) ae p es at =
 
   | ICStableRead ty, [] ->
     SR.Vanilla,
+    (*    IC.compile_static_print env ("ICStableRead" ^ Type.string_of_typ ty) ^^ *)
     Persistence.load env ty
   | ICStableWrite ty, [] ->
     SR.unit,
+    (*    IC.compile_static_print env ("ICStableWrite" ^ Type.string_of_typ ty) ^^ *)
     Persistence.save env ty
 
   (* Cycles *)
diff --git a/src/ir_def/construct.ml b/src/ir_def/construct.ml
index 7d0c53177b3..bca8c8af216 100644
--- a/src/ir_def/construct.ml
+++ b/src/ir_def/construct.ml
@@ -129,6 +129,7 @@ let primE prim es =
     | OtherPrim "rts_max_stack_size" -> T.nat
     | OtherPrim "rts_callback_table_count" -> T.nat
     | OtherPrim "rts_callback_table_size" -> T.nat
+    | OtherPrim "rts_in_install" -> T.bool
     | _ -> assert false (* implement more as needed *)
   in
   let eff = map_max_effs eff es in
diff --git a/src/lowering/desugar.ml b/src/lowering/desugar.ml
index 6a9405dcce5..f77eb62963d 100644
--- a/src/lowering/desugar.ml
+++ b/src/lowering/desugar.ml
@@ -575,9 +575,7 @@ and build_actor at ts exp_opt self_id es obj_typ =
       let v_dom = fresh_var "v_dom" dom in
       let v_rng = fresh_var "v_rng" rng in
       I.{pre = ty'; post = ty},
-      ifE (primE (Ir.RelPrim (T.nat, Operator.EqOp)) [
-               primE (I.OtherPrim "rts_stable_memory_size") [];
-               natE Numerics.Nat.zero])
+      ifE (primE (I.OtherPrim "rts_in_install") [])
         (primE (I.ICStableRead ty) [])
         (letE v (primE (I.ICStableRead ty') [])
            (letE v_dom