diff --git a/src/arch/i386/drivers/net/undi.c b/src/arch/i386/drivers/net/undi.c
index 7e3e7df8..6b830892 100644
--- a/src/arch/i386/drivers/net/undi.c
+++ b/src/arch/i386/drivers/net/undi.c
@@ -9,6 +9,16 @@ reserved.
 $Id$
 ***************************************************************************/
 
+/*
+ * NOTE TO SELF: basemem.c no longer zeroes freed base memory, because
+ * that behaviour is incompatible with librm.  Instead, we must make
+ * sure that the !PXE and PXENV+ structures are rendered unusable
+ * (e.g. by destroying the signature) when we shut down an underlying
+ * pixie.
+ *
+ */
+#warning "undi.c needs to destroy the !PXE signature when freeing a pixie"
+
 /*
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as