diff --git a/scripts/brillo_update_payload b/scripts/brillo_update_payload
index 23d2d7e..d9c18ff 100755
--- a/scripts/brillo_update_payload
+++ b/scripts/brillo_update_payload
@@ -281,7 +281,7 @@
   local option_key="$2"
   local default_value="${3:-}"
   local value
-  if value=$(look "${option_key}=" "${file_txt}" | tail -n 1); then
+  if value=$(grep "^${option_key}=" "${file_txt}" | tail -n 1); then
     if value=$(echo "${value}" | cut -f 2- -d "=" | grep -E "^[0-9]+$"); then
       echo "${value}"
       return