diff --git a/src/core.cpp b/src/core.cpp
index 16e7b27f..f22ca604 100644
--- a/src/core.cpp
+++ b/src/core.cpp
@@ -1806,7 +1806,19 @@ extern "C" RETRO_API bool retro_serialize(void *data, size_t len) {
     if (!sandbox_serialize(sb().transitioning, data, max_size)) return false;
     if (!sandbox_serialize(sb().trans_map != nullptr, data, max_size)) return false;
     if (sb().trans_map != nullptr) {
-        if (!sandbox_serialize(*sb().trans_map, data, max_size)) return false;
+        if (sb().trans_map->isDisposed()) {
+            std::abort();
+        }
+        if (!sb().trans_map->sandbox_serialize_without_hires(data, max_size)) return false;
+        Exception e;
+        Bitmap *hires = sb().trans_map->getHires(e);
+        if (!e.is_ok()) {
+            std::abort();
+        }
+        if (!sandbox_serialize(hires != nullptr, data, max_size)) return false;
+        if (hires != nullptr) {
+            if (!hires->sandbox_serialize_without_hires(data, max_size)) return false;
+        }
     }
     if (!sandbox_serialize(sb().get_movie_from_main_thread() != nullptr, data, max_size)) return false;
     if (sb().get_movie_from_main_thread() != nullptr) {
@@ -2078,15 +2090,41 @@ extern "C" RETRO_API bool retro_unserialize(const void *data, size_t len) {
             if (!sb().transitioning) {
                 DESER_OBJECTS_END_FAIL;
             }
-            if (sb().trans_map == nullptr) {
-                Exception e;
-                sb().trans_map = new Bitmap(e);
+            Exception e;
+            bool is_new = sb().trans_map == nullptr;
+            if (is_new) {
+                sb().trans_map = new Bitmap(e, 1, 1, true);
                 if (e.is_error()) {
                     DESER_OBJECTS_END_FAIL;
                 }
                 sb().trans_map->sandbox_deserialize_begin(true);
             }
-            if (!sandbox_deserialize(*sb().trans_map, data, max_size)) DESER_OBJECTS_END_FAIL;
+            Bitmap *hires = sb().trans_map->getHires(e);
+            if (e.is_error()) {
+                DESER_OBJECTS_END_FAIL;
+            }
+            if (hires != nullptr) {
+                hires->sandbox_deserialize_begin(is_new);
+            }
+            if (!sb().trans_map->sandbox_deserialize_without_hires(data, max_size)) DESER_OBJECTS_END_FAIL;
+            bool have_trans_map_hires;
+            if (!sandbox_deserialize(have_trans_map_hires, data, max_size)) DESER_OBJECTS_END_FAIL;
+            if (e.is_error()) {
+                DESER_OBJECTS_END_FAIL;
+            }
+            if (have_trans_map_hires && hires == nullptr) {
+                hires = new Bitmap(e, 1, 1, true);
+                if (e.is_error()) {
+                    DESER_OBJECTS_END_FAIL;
+                }
+                hires->sandbox_deserialize_begin(true);
+            } else if (!have_trans_map_hires && hires != nullptr) {
+                delete hires;
+                hires = nullptr;
+            }
+            if (hires != nullptr) {
+                if (!hires->sandbox_deserialize_without_hires(data, max_size)) DESER_OBJECTS_END_FAIL;
+            }
         } else {
             if (sb().trans_map != nullptr) {
                 delete sb().trans_map;
@@ -2110,6 +2148,15 @@ extern "C" RETRO_API bool retro_unserialize(const void *data, size_t len) {
 
     if (sb().trans_map != nullptr) {
         sb().trans_map->sandbox_deserialize_end(false);
+        Exception e;
+        Bitmap *hires = sb().trans_map->getHires(e);
+        if (e.is_error()) {
+            DESER_OBJECTS_END_FAIL;
+        }
+        if (hires != nullptr) {
+            sb().trans_map->setHiresRaw(e, hires);
+            hires->sandbox_deserialize_end(false);
+        }
     }
     for (const auto &object : sb()->objects) {
         if (object.typenum > 0) {
diff --git a/src/display/bitmap.cpp b/src/display/bitmap.cpp
index 35d9cbb1..4991ccd8 100644
--- a/src/display/bitmap.cpp
+++ b/src/display/bitmap.cpp
@@ -1335,6 +1335,13 @@ Bitmap *Bitmap::getHires(Exception &exception) const {
     return p->selfHires;
 }
 
+void Bitmap::setHiresRaw(Exception &exception, Bitmap *hires) {
+    GUARD(guardDisposed(exception));
+
+    GUARD(hires->setLoresRaw(exception, this));
+    p->selfHires = hires;
+}
+
 void Bitmap::setHires(Exception &exception, Bitmap *hires) {
     GUARD(guardDisposed(exception));
 
@@ -1343,6 +1350,12 @@ void Bitmap::setHires(Exception &exception, Bitmap *hires) {
     p->selfHires = hires;
 }
 
+void Bitmap::setLoresRaw(Exception &exception, Bitmap *lores) {
+    GUARD(guardDisposed(exception));
+
+    p->selfLores = lores;
+}
+
 void Bitmap::setLores(Exception &exception, Bitmap *lores) {
     GUARD(guardDisposed(exception));
 
@@ -3683,7 +3696,7 @@ void Bitmap::loresDisposal()
 }
 
 #ifdef MKXPZ_RETRO
-bool Bitmap::sandbox_serialize(void *&data, mkxp_sandbox::wasm_size_t &max_size) const
+bool Bitmap::sandbox_serialize_without_hires(void *&data, mkxp_sandbox::wasm_size_t &max_size) const
 {
     if (!mkxp_sandbox::sandbox_serialize((int32_t)width(), data, max_size)) return false;
     if (!mkxp_sandbox::sandbox_serialize((int32_t)height(), data, max_size)) return false;
@@ -3712,9 +3725,15 @@ bool Bitmap::sandbox_serialize(void *&data, mkxp_sandbox::wasm_size_t &max_size)
     }
 
     if (!mkxp_sandbox::sandbox_serialize(p->font == &shState->defaultFont() ? nullptr : p->font, data, max_size)) return false;
+
+    return true;
+}
+
+bool Bitmap::sandbox_serialize(void *&data, mkxp_sandbox::wasm_size_t &max_size) const
+{
+    if (!sandbox_serialize_without_hires(data, max_size)) return false;
     if (!mkxp_sandbox::sandbox_serialize(p->selfHires, data, max_size)) return false;
     if (!mkxp_sandbox::sandbox_serialize(p->selfLores, data, max_size)) return false;
-
     return true;
 }
 
@@ -3756,7 +3775,7 @@ bool Bitmap::sandbox_serialize_pixels(void *&data, mkxp_sandbox::wasm_size_t &ma
     return true;
 }
 
-bool Bitmap::sandbox_deserialize(const void *&data, mkxp_sandbox::wasm_size_t &max_size)
+bool Bitmap::sandbox_deserialize_without_hires(const void *&data, mkxp_sandbox::wasm_size_t &max_size)
 {
     int32_t old_width = width();
     int32_t old_height = height();
@@ -3994,9 +4013,15 @@ bool Bitmap::sandbox_deserialize(const void *&data, mkxp_sandbox::wasm_size_t &m
     if (p->font == nullptr) {
         p->font = &shState->defaultFont();
     }
+
+    return true;
+}
+
+bool Bitmap::sandbox_deserialize(const void *&data, mkxp_sandbox::wasm_size_t &max_size)
+{
+    if (!sandbox_deserialize_without_hires(data, max_size)) return false;
     if (!mkxp_sandbox::sandbox_deserialize(p->selfHires, data, max_size)) return false;
     if (!mkxp_sandbox::sandbox_deserialize(p->selfLores, data, max_size)) return false;
-
     return true;
 }
 
diff --git a/src/display/bitmap.h b/src/display/bitmap.h
index e7b64fd8..50f76d3f 100644
--- a/src/display/bitmap.h
+++ b/src/display/bitmap.h
@@ -88,7 +88,9 @@ public:
 	int getWidth(Exception &exception)  const;
 	int getHeight(Exception &exception) const;
 	bool getHasHires(Exception &exception) const;
+	void setHiresRaw(Exception &exception, Bitmap *hires);
 	DECL_ATTR(Hires, Bitmap*)
+	void setLoresRaw(Exception &exception, Bitmap *lores);
 	void setLores(Exception &exception, Bitmap *lores);
 	bool getIsMega(Exception &exception) const;
 	bool getIsAnimated(Exception &exception) const;
@@ -218,7 +220,9 @@ public:
     void assumeRubyGC(bool value = true);
 
 #ifdef MKXPZ_RETRO
+	bool sandbox_serialize_without_hires(void *&data, mkxp_sandbox::wasm_size_t &max_size) const;
 	bool sandbox_serialize(void *&data, mkxp_sandbox::wasm_size_t &max_size) const;
+	bool sandbox_deserialize_without_hires(const void *&data, mkxp_sandbox::wasm_size_t &max_size);
 	bool sandbox_deserialize(const void *&data, mkxp_sandbox::wasm_size_t &max_size);
 	void sandbox_deserialize_begin(bool is_new);
 	void sandbox_deserialize_end(bool is_sandbox_object);