diff --git a/src/sl/debug_sl.cpp b/src/sl/debug_sl.cpp
index 0a8df9d242..7eb603eb5e 100644
--- a/src/sl/debug_sl.cpp
+++ b/src/sl/debug_sl.cpp
@@ -108,8 +108,8 @@ static void Check_DBGD()
 }
 
 extern const ChunkHandler debug_chunk_handlers[] = {
-	{ 'DBGL',   nullptr, Load_DBGL, nullptr, Check_DBGL, CH_UNUSED },
-	{ 'DBGC',   nullptr, Load_DBGC, nullptr, Check_DBGC, CH_UNUSED },
+	{ 'DBGL',   nullptr, Load_DBGL, nullptr, Check_DBGL, CH_READONLY },
+	{ 'DBGC',   nullptr, Load_DBGC, nullptr, Check_DBGC, CH_READONLY },
 	{ 'DBGD', Save_DBGD, Load_DBGD, nullptr, Check_DBGD, CH_TABLE },
 };
 
diff --git a/src/sl/misc_sl.cpp b/src/sl/misc_sl.cpp
index 44cd01f2f6..a3c1534f1a 100644
--- a/src/sl/misc_sl.cpp
+++ b/src/sl/misc_sl.cpp
@@ -210,7 +210,7 @@ static void Load_MISC()
 static const ChunkHandler misc_chunk_handlers[] = {
 	{ 'DATE', Save_DATE, Load_DATE, nullptr, Check_DATE, CH_TABLE },
 	MakeSaveUpstreamFeatureConditionalLoadUpstreamChunkHandler<'VIEW', XSLFI_TABLE_MISC_SL>(Load_VIEW, nullptr, nullptr),
-	{ 'MISC', nullptr, Load_MISC, nullptr, nullptr, CH_UNUSED },
+	{ 'MISC', nullptr, Load_MISC, nullptr, nullptr, CH_READONLY },
 };
 
 extern const ChunkHandlerTable _misc_chunk_handlers(misc_chunk_handlers);
diff --git a/src/sl/saveload.h b/src/sl/saveload.h
index 31e8a02d97..291630e9fb 100644
--- a/src/sl/saveload.h
+++ b/src/sl/saveload.h
@@ -112,7 +112,7 @@ enum ChunkType {
 	CH_SPARSE_TABLE = 4,
 	CH_EXT_HDR      = 15, ///< Extended chunk header
 
-	CH_UNUSED = 0x80,
+	CH_READONLY = 0x80,
 };
 
 /** Handlers and description of chunk. */
@@ -180,7 +180,7 @@ namespace upstream_sl {
 			SlUnreachablePlaceholder,
 			SlUnreachablePlaceholder,
 			SlUnreachablePlaceholder,
-			CH_UNUSED
+			CH_READONLY
 		};
 		ch.special_proc = [](uint32_t chunk_id, ChunkSaveLoadSpecialOp op) -> ChunkSaveLoadSpecialOpResult {
 			assert(id == chunk_id);
@@ -262,7 +262,7 @@ namespace upstream_sl {
 	template <uint32_t id, SlXvFeatureIndex feature, uint16_t min_version = 1, uint16_t max_version = 0xFFFF>
 	ChunkHandler MakeSaveUpstreamFeatureConditionalLoadUpstreamChunkHandler(ChunkSaveLoadProc *load_proc, ChunkSaveLoadProc *ptrs_proc, ChunkSaveLoadProc *load_check_proc)
 	{
-		return MakeConditionallyUpstreamChunkHandler<id, SaveUpstreamFeatureConditionalLoadUpstreamChunkInfo<feature, min_version, max_version>>(nullptr, load_proc, ptrs_proc, load_check_proc, CH_UNUSED);
+		return MakeConditionallyUpstreamChunkHandler<id, SaveUpstreamFeatureConditionalLoadUpstreamChunkInfo<feature, min_version, max_version>>(nullptr, load_proc, ptrs_proc, load_check_proc, CH_READONLY);
 	}
 }