diff --git a/.gitmodules b/.gitmodules
index 4277205..30be60d 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,4 +1,3 @@
 [submodule "backend/quicly-go"]
 	path = backend/quicly-go
 	url = https://github.com/Project-Faster/quicly-go.git
-	branch = debug
diff --git a/backend/quicly-go b/backend/quicly-go
index 2f652b4..ac27085 160000
--- a/backend/quicly-go
+++ b/backend/quicly-go
@@ -1 +1 @@
-Subproject commit 2f652b45eb50cca1efcf43039db0c23bda4cbb5b
+Subproject commit ac270855157787037df646145749689b270a1521