Index: usr.sbin/bsdinstall/scripts/script
===================================================================
--- usr.sbin/bsdinstall/scripts/script
+++ usr.sbin/bsdinstall/scripts/script
@@ -92,6 +92,7 @@
 
 split -a 2 -p '^#!.*' "$SCRIPT" $TMPDIR/bsdinstall-installscript-
 
+: ${BSDINSTALL_LOG="${debugFile#+}"}
 . $TMPDIR/bsdinstall-installscript-aa
 : ${DISTRIBUTIONS="kernel.txz base.txz"}; export DISTRIBUTIONS
 export BSDINSTALL_DISTDIR