Update bom.py
diff --git a/erpnext/manufacturing/doctype/bom/bom.py b/erpnext/manufacturing/doctype/bom/bom.py
index c0960cb..6730141 100644
--- a/erpnext/manufacturing/doctype/bom/bom.py
+++ b/erpnext/manufacturing/doctype/bom/bom.py
@@ -185,13 +185,13 @@
 			item = frappe.get_doc("Item", self.item)
 			if item.default_bom != self.name:
 				item.default_bom = self.name
-				item.save()
+				item.save(ignore_permissions = True)
 		else:
 			frappe.db.set(self, "is_default", 0)
 			item = frappe.get_doc("Item", self.item)
 			if item.default_bom == self.name:
 				item.default_bom = None
-				item.save()
+				item.save(ignore_permissions = True)
 
 	def clear_operations(self):
 		if not self.with_operations: