Index: io_kicad_legacy.c
===================================================================
--- io_kicad_legacy.c	(revision 27313)
+++ io_kicad_legacy.c	(revision 27314)
@@ -65,7 +65,8 @@
 	io_kicad_legacy.parse_pcb = NULL;
 	io_kicad_legacy.parse_footprint = NULL;
 	io_kicad_legacy.parse_font = NULL;
-	io_kicad_legacy.write_buffer = io_kicad_legacy_write_buffer;
+	io_kicad_legacy.write_buffer = NULL;
+	io_kicad_legacy.write_buffer_subc = io_kicad_legacy_write_buffer_subc;
 	io_kicad_legacy.write_footprint = io_kicad_legacy_write_element;
 	io_kicad_legacy.write_pcb = io_kicad_legacy_write_pcb;
 	io_kicad_legacy.default_fmt = "kicadl";
Index: write.c
===================================================================
--- write.c	(revision 27313)
+++ write.c	(revision 27314)
@@ -663,8 +663,13 @@
 	}
 }
 
-int io_kicad_legacy_write_buffer(pcb_plug_io_t *ctx, FILE *FP, pcb_buffer_t *buff, pcb_bool elem_only)
+int io_kicad_legacy_write_buffer_subc(pcb_plug_io_t *ctx, FILE *FP, pcb_buffer_t *buff, long idx)
 {
+	if (idx != 0) {
+		pcb_message(PCB_MSG_ERROR, "Only the first subcircuit can be saved at the moment\n");
+		return -1;
+	}
+
 	if (pcb_subclist_length(&buff->Data->subc) == 0) {
 		pcb_message(PCB_MSG_ERROR, "Buffer has no subcircuits!\n");
 		return -1;
Index: write.h
===================================================================
--- write.h	(revision 27313)
+++ write.h	(revision 27314)
@@ -31,5 +31,5 @@
 #include "data.h"
 
 int io_kicad_legacy_write_element(pcb_plug_io_t *ctx, FILE *FP, pcb_data_t *Data);
-int io_kicad_legacy_write_buffer(pcb_plug_io_t *ctx, FILE *FP, pcb_buffer_t *buff, pcb_bool elem_only);
+int io_kicad_legacy_write_buffer_subc(pcb_plug_io_t *ctx, FILE *FP, pcb_buffer_t *buff, long idx);
 int io_kicad_legacy_write_pcb(pcb_plug_io_t *ctx, FILE *FP, const char *old_filename, const char *new_filename, pcb_bool emergency);