diff --git a/usr.sbin/bsdinstall/scripts/jail b/usr.sbin/bsdinstall/scripts/jail
--- a/usr.sbin/bsdinstall/scripts/jail
+++ b/usr.sbin/bsdinstall/scripts/jail
@@ -61,11 +61,13 @@
 rm -rf $BSDINSTALL_TMPETC
 mkdir $BSDINSTALL_TMPETC
 mkdir -p $1 || error "mkdir failed for $1"
+rm -rf $TMPDIR/bsdinstall-installscript-*
 
 if [ -n "$SCRIPT" ]
 then
-        split -a 2 -p '^#!.*' "$SCRIPT" $TMPDIR/bsdinstall-installscript-
-        . $TMPDIR/bsdinstall-installscript-aa
+	split -a 2 -p '^#!.*' "$SCRIPT" $TMPDIR/bsdinstall-installscript-
+	mv $TMPDIR/bsdinstall-installscript-aa $TMPDIR/bsdinstall-installscript-options
+	. $TMPDIR/bsdinstall-installscript-options
 fi
 
 test ! -d $BSDINSTALL_DISTDIR && mkdir -p $BSDINSTALL_DISTDIR
@@ -147,7 +149,7 @@
 
 # Run post-install script
 if [ -f $TMPDIR/bsdinstall-installscript-ab ]; then
-	cp $TMPDIR/bsdinstall-installscript-ab $BSDINSTALL_CHROOT/tmp/installscript
+	cat $TMPDIR/bsdinstall-installscript-?? >$BSDINSTALL_CHROOT/tmp/installscript
 	chmod a+x $BSDINSTALL_CHROOT/tmp/installscript
 	mount -t devfs devfs "$BSDINSTALL_CHROOT/dev"
 	chroot $BSDINSTALL_CHROOT /tmp/installscript $@ 2>&1
diff --git a/usr.sbin/bsdinstall/scripts/script b/usr.sbin/bsdinstall/scripts/script
--- a/usr.sbin/bsdinstall/scripts/script
+++ b/usr.sbin/bsdinstall/scripts/script
@@ -88,10 +88,12 @@
 f_dprintf "Began Installation at %s" "$( date )"
 rm -rf $BSDINSTALL_TMPETC
 mkdir $BSDINSTALL_TMPETC
+rm -rf $TMPDIR/bsdinstall-installscript-*
 
 split -a 2 -p '^#!.*' "$SCRIPT" $TMPDIR/bsdinstall-installscript-
 
-. $TMPDIR/bsdinstall-installscript-aa
+mv $TMPDIR/bsdinstall-installscript-aa $TMPDIR/bsdinstall-installscript-options
+. $TMPDIR/bsdinstall-installscript-options
 : ${DISTRIBUTIONS="kernel.txz base.txz"}; export DISTRIBUTIONS
 export BSDINSTALL_DISTDIR
 
@@ -159,7 +161,7 @@
 
 # Run post-install script
 if [ -f $TMPDIR/bsdinstall-installscript-ab ]; then
-	cp $TMPDIR/bsdinstall-installscript-ab $BSDINSTALL_CHROOT/tmp/installscript
+	cat $TMPDIR/bsdinstall-installscript-?? >$BSDINSTALL_CHROOT/tmp/installscript
 	chmod a+x $BSDINSTALL_CHROOT/tmp/installscript
 	chroot $BSDINSTALL_CHROOT /tmp/installscript $@ 2>&1
 	rm $BSDINSTALL_CHROOT/tmp/installscript