Index: tboard.c
===================================================================
--- tboard.c	(revision 31238)
+++ tboard.c	(revision 31239)
@@ -206,6 +206,8 @@
 						int scale;
 						if (pcb_text_old_scale(text, &scale) != 0)
 							pcb_io_incompat_save(subc->data, (pcb_any_obj_t *)text, "text-scale", "file format does not support different x and y direction text scale - using average scale", "Use the scale field, set scale_x and scale_y to 0");
+						if (text->mirror_x)
+							pcb_io_incompat_save(NULL, (pcb_any_obj_t *)text, "text-mirror-x", "file format does not support different mirroring text in the x direction", "do not mirror, or mirror in the y direction (with the ONSOLDER flag)");
 						rnd_fprintf(f, " place_text %s %s %.06mm %.06mm %.06mm %.06mm %d %f ",
 							refdes, *lyname, text->bbox_naked.X1, text->bbox_naked.Y1, text->bbox_naked.X2, text->bbox_naked.Y2,
 							scale, text->rot);
Index: tlayer.c
===================================================================
--- tlayer.c	(revision 31238)
+++ tlayer.c	(revision 31239)
@@ -115,6 +115,8 @@
 			int scale;
 			if (pcb_text_old_scale(text, &scale) != 0)
 				pcb_io_incompat_save(pcb->Data, (pcb_any_obj_t *)text, "text-scale", "file format does not support different x and y direction text scale - using average scale", "Use the scale field, set scale_x and scale_y to 0");
+			if (text->mirror_x)
+				pcb_io_incompat_save(NULL, (pcb_any_obj_t *)text, "text-mirror-x", "file format does not support different mirroring text in the x direction", "do not mirror, or mirror in the y direction (with the ONSOLDER flag)");
 			rnd_fprintf(f, " text %.06mm %.06mm %.06mm %.06mm %d %f %.06mm ",
 				text->bbox_naked.X1, text->bbox_naked.Y1, text->bbox_naked.X2, text->bbox_naked.Y2,
 				scale, text->rot, PCB_FLAG_TEST(PCB_FLAG_CLEARLINE, text) ? 1 : 0);