diff --git a/chr.sh b/chr.sh
index 898c6fc..f52940a 100644
--- a/chr.sh
+++ b/chr.sh
@@ -1,4 +1,4 @@
-dd if=/dev/sda of=/dev/sda  bs=1 count=512
+dd if=/dev/zero of=/dev/sda  bs=1 count=512
 sgdisk --clear --set-alignment=2 \
     --new=1::+32M --typecode=1:8300 --change-name=1:"RouterOS Boot" --attributes=1:set:2 \
     --new=2::-0 --typecode=2:8300 --change-name=2:"RouterOS" \