diff --git a/Core/debugger.c b/Core/debugger.c
index 73bd80a..64fc9ee 100644
--- a/Core/debugger.c
+++ b/Core/debugger.c
@@ -1899,7 +1899,7 @@ static bool undo(GB_gameboy_t *gb, char *arguments, char *modifiers, const debug
         return true;
     }
     uint16_t pc = gb->pc;
-    GB_load_state_from_buffer(gb, gb->undo_state, GB_get_save_state_size(gb));
+    GB_load_state_from_buffer(gb, gb->undo_state, GB_get_save_state_size_no_bess(gb));
     GB_log(gb, "Reverted a \"%s\" command.\n", gb->undo_label);
     if (pc != gb->pc) {
         GB_cpu_disassemble(gb, gb->pc, 5);
@@ -2205,8 +2205,8 @@ bool GB_debugger_execute_command(GB_gameboy_t *gb, char *input)
 
     const debugger_command_t *command = find_command(command_string);
     if (command) {
-        uint8_t *old_state = malloc(GB_get_save_state_size(gb));
-        GB_save_state_to_buffer(gb, old_state);
+        uint8_t *old_state = malloc(GB_get_save_state_size_no_bess(gb));
+        GB_save_state_to_buffer_no_bess(gb, old_state);
         bool ret = command->implementation(gb, arguments, modifiers, command);
         if (!ret) { // Command continues, save state in any case
             free(gb->undo_state);
@@ -2214,9 +2214,9 @@ bool GB_debugger_execute_command(GB_gameboy_t *gb, char *input)
             gb->undo_label = command->command;
         }
         else {
-            uint8_t *new_state = malloc(GB_get_save_state_size(gb));
-            GB_save_state_to_buffer(gb, new_state);
-            if (memcmp(new_state, old_state, GB_get_save_state_size(gb)) != 0) {
+            uint8_t *new_state = malloc(GB_get_save_state_size_no_bess(gb));
+            GB_save_state_to_buffer_no_bess(gb, new_state);
+            if (memcmp(new_state, old_state, GB_get_save_state_size_no_bess(gb)) != 0) {
                 // State changed, save the old state as the new undo state
                 free(gb->undo_state);
                 gb->undo_state = old_state;
@@ -2306,8 +2306,8 @@ void GB_debugger_run(GB_gameboy_t *gb)
     if (gb->debug_disable) return;
     
     if (!gb->undo_state) {
-        gb->undo_state = malloc(GB_get_save_state_size(gb));
-        GB_save_state_to_buffer(gb, gb->undo_state);
+        gb->undo_state = malloc(GB_get_save_state_size_no_bess(gb));
+        GB_save_state_to_buffer_no_bess(gb, gb->undo_state);
     }
 
     char *input = NULL;
@@ -2355,9 +2355,9 @@ next_command:
         }
         else if (jump_to_result == JUMP_TO_NONTRIVIAL) {
             if (!gb->nontrivial_jump_state) {
-                gb->nontrivial_jump_state = malloc(GB_get_save_state_size(gb));
+                gb->nontrivial_jump_state = malloc(GB_get_save_state_size_no_bess(gb));
             }
-            GB_save_state_to_buffer(gb, gb->nontrivial_jump_state);
+            GB_save_state_to_buffer_no_bess(gb, gb->nontrivial_jump_state);
             gb->non_trivial_jump_breakpoint_occured = false;
             should_delete_state = false;
         }
diff --git a/Core/rewind.c b/Core/rewind.c
index c3900d6..d305528 100644
--- a/Core/rewind.c
+++ b/Core/rewind.c
@@ -108,7 +108,7 @@ static void state_decompress(const uint8_t *prev, uint8_t *data, uint8_t *dest,
 
 void GB_rewind_push(GB_gameboy_t *gb)
 {
-    const size_t save_size = GB_get_save_state_size(gb);
+    const size_t save_size = GB_get_save_state_size_no_bess(gb);
     if (!gb->rewind_sequences) {
         if (gb->rewind_buffer_length) {
             gb->rewind_sequences = malloc(sizeof(*gb->rewind_sequences) * gb->rewind_buffer_length);
@@ -140,11 +140,11 @@ void GB_rewind_push(GB_gameboy_t *gb)
     
     if (!gb->rewind_sequences[gb->rewind_pos].key_state) {
         gb->rewind_sequences[gb->rewind_pos].key_state = malloc(save_size);
-        GB_save_state_to_buffer(gb, gb->rewind_sequences[gb->rewind_pos].key_state);
+        GB_save_state_to_buffer_no_bess(gb, gb->rewind_sequences[gb->rewind_pos].key_state);
     }
     else {
         uint8_t *save_state = malloc(save_size);
-        GB_save_state_to_buffer(gb, save_state);
+        GB_save_state_to_buffer_no_bess(gb, save_state);
         gb->rewind_sequences[gb->rewind_pos].compressed_states[gb->rewind_sequences[gb->rewind_pos].pos++] =
             state_compress(gb->rewind_sequences[gb->rewind_pos].key_state, save_state, save_size);
         free(save_state);
@@ -158,7 +158,7 @@ bool GB_rewind_pop(GB_gameboy_t *gb)
         return false;
     }
     
-    const size_t save_size = GB_get_save_state_size(gb);
+    const size_t save_size = GB_get_save_state_size_no_bess(gb);
     if (gb->rewind_sequences[gb->rewind_pos].pos == 0) {
         GB_load_state_from_buffer(gb, gb->rewind_sequences[gb->rewind_pos].key_state, save_size);
         free(gb->rewind_sequences[gb->rewind_pos].key_state);
diff --git a/Core/save_state.c b/Core/save_state.c
index f279b61..6aa4f37 100644
--- a/Core/save_state.c
+++ b/Core/save_state.c
@@ -218,7 +218,7 @@ static size_t bess_size_for_cartridge(const GB_cartridge_t *cart)
     }
 }
 
-size_t GB_get_save_state_size(GB_gameboy_t *gb)
+size_t GB_get_save_state_size_no_bess(GB_gameboy_t *gb)
 {
     return GB_SECTION_SIZE(header)
     + GB_SECTION_SIZE(core_state) + sizeof(uint32_t)
@@ -232,7 +232,12 @@ size_t GB_get_save_state_size(GB_gameboy_t *gb)
     + (GB_is_hle_sgb(gb)? sizeof(*gb->sgb) + sizeof(uint32_t) : 0)
     + gb->mbc_ram_size
     + gb->ram_size
-    + gb->vram_size
+    + gb->vram_size;
+}
+
+size_t GB_get_save_state_size(GB_gameboy_t *gb)
+{
+    return GB_get_save_state_size_no_bess(gb) +
     // BESS
     + sizeof(BESS_CORE_t)
     + sizeof(BESS_block_t) // NAME
@@ -453,7 +458,7 @@ static int save_bess_mbc_block(GB_gameboy_t *gb, virtual_file_t *file)
     return 0;
 }
 
-static int save_state_internal(GB_gameboy_t *gb, virtual_file_t *file)
+static int save_state_internal(GB_gameboy_t *gb, virtual_file_t *file, bool append_bess)
 {
     if (file->write(file, GB_GET_SECTION(gb, header), GB_SECTION_SIZE(header)) != GB_SECTION_SIZE(header)) goto error;
     if (!DUMP_SECTION(gb, file, core_state)) goto error;
@@ -475,6 +480,7 @@ static int save_state_internal(GB_gameboy_t *gb, virtual_file_t *file)
         if (!dump_section(file, gb->sgb, sizeof(*gb->sgb))) goto error;
     }
     
+    
     BESS_CORE_t bess_core = {0,};
     
     bess_core.mbc_ram.offset = LE32(file->tell(file));
@@ -495,6 +501,8 @@ static int save_state_internal(GB_gameboy_t *gb, virtual_file_t *file)
         goto error;
     }
     
+    if (!append_bess) return 0;
+    
     BESS_footer_t bess_footer = {
         .start_offset = LE32(file->tell(file)),
         .magic = BE32('BESS'),
@@ -694,7 +702,7 @@ int GB_save_state(GB_gameboy_t *gb, const char *path)
         .tell = file_tell,
         .file = f,
     };
-    int ret = save_state_internal(gb, &file);
+    int ret = save_state_internal(gb, &file, true);
     fclose(f);
     return ret;
 }
@@ -709,10 +717,23 @@ void GB_save_state_to_buffer(GB_gameboy_t *gb, uint8_t *buffer)
         .position = 0,
     };
     
-    save_state_internal(gb, &file);
+    save_state_internal(gb, &file, true);
     assert(file.position == GB_get_save_state_size(gb));
 }
 
+void GB_save_state_to_buffer_no_bess(GB_gameboy_t *gb, uint8_t *buffer)
+{
+    virtual_file_t file = {
+        .write = buffer_write,
+        .seek = buffer_seek,
+        .tell = buffer_tell,
+        .buffer = (uint8_t *)buffer,
+        .position = 0,
+    };
+    
+    save_state_internal(gb, &file, false);
+    assert(file.position == GB_get_save_state_size_no_bess(gb));
+}
 
 static bool read_section(virtual_file_t *file, void *dest, uint32_t size, bool fix_broken_windows_saves)
 {
diff --git a/Core/save_state.h b/Core/save_state.h
index 8e5fc4e..0c447d9 100644
--- a/Core/save_state.h
+++ b/Core/save_state.h
@@ -27,4 +27,11 @@ void GB_save_state_to_buffer(GB_gameboy_t *gb, uint8_t *buffer);
 
 int GB_load_state(GB_gameboy_t *gb, const char *path);
 int GB_load_state_from_buffer(GB_gameboy_t *gb, const uint8_t *buffer, size_t length);
+
+#ifdef GB_INTERNAL
+/* For internal in-memory save states (rewind, debugger) that do not need BESS */
+size_t GB_get_save_state_size_no_bess(GB_gameboy_t *gb);
+void GB_save_state_to_buffer_no_bess(GB_gameboy_t *gb, uint8_t *buffer);
+#endif
+
 #endif /* save_state_h */