diff --git a/build.sh b/build.sh
index aaa690d..36c6ac8 100755
--- a/build.sh
+++ b/build.sh
@@ -28,7 +28,7 @@ PLATFORM="linux/arm/v7"
 
 set -eu
 
-if [[ ! -d ./tailscale/.git ]]
+if [ ! -d ./tailscale/.git ]
 then
     git clone https://github.com/tailscale/tailscale.git
 fi