diff --git a/tests/echo1.sh b/tests/echo1.sh
index 4c4dec92..ec9bca7f 100755
--- a/tests/echo1.sh
+++ b/tests/echo1.sh
@@ -15,7 +15,10 @@ sleep 0.1
 curl -N "http://localhost:${PORT}/vfs/a.txt" --max-time 5
 
 sleep 0.1
-curl -N "http://localhost:${PORT}/vfs/a.txt" -H 'accept-encoding: deflate' --max-time 5 | base64
+# NOTE: the sed is there because of a timing/deflate non determinism. Both strings
+# decompress to the same "hello\nworld\n" but which one is picked depends on
+# the machine/library/… ?? but both are valid.
+curl -N "http://localhost:${PORT}/vfs/a.txt" -H 'accept-encoding: deflate' --max-time 5 | base64 | sed 's+ykjNycnnKs8vyknhAgAAAP//AwA=+ykjNycnnKs8vyknhAgAAAP+'
 
 sleep 0.1
 curl -N "http://localhost:${PORT}/vfs/sub/yolo.html" --max-time 5