diff --git a/bash/hetzner-rescue.sh b/bash/hetzner-rescue.sh
index 261c7e5..2182e15 100644
--- a/bash/hetzner-rescue.sh
+++ b/bash/hetzner-rescue.sh
@@ -189,7 +189,7 @@ function hetzner-rescue-wipe-12-10-10-0 {
         echo ; echo "#${number}: ${device}"
         # format esp
         dd \
-        if='/dev/zero' of="${device}3"
+        if='/dev/zero' of="${device}3" bs='1M'
         mkfs.vfat -F 32 -n "esp-${number}" "${device}3"
     done
     #