diff --git a/scripts/setup_bls_build_flags.sh b/scripts/setup_bls_build_flags.sh
index e5af7f57d..13d4f4695 100644
--- a/scripts/setup_bls_build_flags.sh
+++ b/scripts/setup_bls_build_flags.sh
@@ -6,15 +6,19 @@ case "${0}" in
 *) progdir=.;;
 esac
 
-unset -v gopath
-gopath=$(go env GOPATH)
-# HMY_PATH is the common root directory of all harmony repos
-HMY_PATH="${gopath%%:*}/src/github.com/harmony-one"
-if [ ! -d $HMY_PATH ]; then
-   # "env pwd" uses external pwd(1) implementation and not the Bash built-in,
-   # which does not fully dereference symlinks.
-   HMY_PATH=$(cd $progdir/../.. && env pwd)
-fi
+case "${HMY_PATH+set}" in
+"")
+   unset -v gopath
+   gopath=$(go env GOPATH)
+   # HMY_PATH is the common root directory of all harmony repos
+   HMY_PATH="${gopath%%:*}/src/github.com/harmony-one"
+   if [ ! -d $HMY_PATH ]; then
+      # "env pwd" uses external pwd(1) implementation and not the Bash built-in,
+      # which does not fully dereference symlinks.
+      HMY_PATH=$(cd $progdir/../.. && env pwd)
+   fi
+   ;;
+esac
 : ${OPENSSL_DIR="/usr/local/opt/openssl"}
 : ${MCL_DIR="${HMY_PATH}/mcl"}
 : ${BLS_DIR="${HMY_PATH}/bls"}