Index: layer.c
===================================================================
--- layer.c	(revision 21118)
+++ layer.c	(revision 21119)
@@ -1153,7 +1153,6 @@
 {
 	static pcb_layer_id_t cache = -1;
 	pcb_layer_id_t id = pcb_layer_get_cached(PCB, &cache, PCB_LYT_BOTTOM, PCB_LYT_SILK);
-	assert(id >= 0);
 	return id;
 }
 
@@ -1161,6 +1160,5 @@
 {
 	static pcb_layer_id_t cache = -1;
 	pcb_layer_id_t id = pcb_layer_get_cached(PCB, &cache, PCB_LYT_TOP, PCB_LYT_SILK);
-	assert(id >= 0);
 	return id;
 }