diff --git a/bin/flatcar-update b/bin/flatcar-update
index 2d12735..7b7d2a5 100755
--- a/bin/flatcar-update
+++ b/bin/flatcar-update
@@ -280,7 +280,7 @@ tee /tmp/response-server > /dev/null <<'EOF'
 #!/bin/bash
 set -euo pipefail
 read -a WORDS
-if [[ ${#WORDS[@]} -ne 3 -o ${WORDS[0]} != POST -o ${WORDS[1]} != /update ]] ; then
+if [[ ${#WORDS[@]} -ne 3 ]] || [[ ${WORDS[0]} != POST ]] || [[ ${WORDS[1]} != /update ]] ; then
   echo -ne "HTTP/1.1 400 Bad request\r\n\r\n"; exit 0
 fi
 echo -ne "HTTP/1.1 200 OK\r\n"