diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 70a9c76e..6e80882c 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "1.6.3"
+  ".": "1.6.4"
 }
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9e89d42b..fd9be04d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## 1.6.4 (2026-04-23)
+
+Full Changelog: [v1.6.3...v1.6.4](https://github.com/OneBusAway/ruby-sdk/compare/v1.6.3...v1.6.4)
+
+### Chores
+
+* **internal:** more robust bootstrap script ([56b8c52](https://github.com/OneBusAway/ruby-sdk/commit/56b8c5202f166658c5e0ab69d83d674d426906be))
+
 ## 1.6.3 (2026-04-18)
 
 Full Changelog: [v1.6.2...v1.6.3](https://github.com/OneBusAway/ruby-sdk/compare/v1.6.2...v1.6.3)
diff --git a/Gemfile.lock b/Gemfile.lock
index 631cb94f..c6106c88 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -11,7 +11,7 @@ GIT
 PATH
   remote: .
   specs:
-    onebusaway-sdk (1.6.3)
+    onebusaway-sdk (1.6.4)
       cgi
       connection_pool
 
diff --git a/README.md b/README.md
index d920b4f4..cd69176e 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@ To use this gem, install via Bundler by adding the following to your application
 <!-- x-release-please-start-version -->
 
 ```ruby
-gem "onebusaway-sdk", "~> 1.6.3"
+gem "onebusaway-sdk", "~> 1.6.4"
 ```
 
 <!-- x-release-please-end -->
diff --git a/lib/onebusaway_sdk/version.rb b/lib/onebusaway_sdk/version.rb
index 48c58ccb..bf1cae08 100644
--- a/lib/onebusaway_sdk/version.rb
+++ b/lib/onebusaway_sdk/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module OnebusawaySDK
-  VERSION = "1.6.3"
+  VERSION = "1.6.4"
 end
diff --git a/scripts/bootstrap b/scripts/bootstrap
index 34878642..a5e1b80a 100755
--- a/scripts/bootstrap
+++ b/scripts/bootstrap
@@ -4,7 +4,7 @@ set -e
 
 cd -- "$(dirname -- "$0")/.."
 
-if [ -f "Brewfile" ] && [ "$(uname -s)" = "Darwin" ] && [ "$SKIP_BREW" != "1" ] && [ -t 0 ]; then
+if [ -f "Brewfile" ] && [ "$(uname -s)" = "Darwin" ] && [ "${SKIP_BREW:-}" != "1" ] && [ -t 0 ]; then
   brew bundle check >/dev/null 2>&1 || {
     echo -n "==> Install Homebrew dependencies? (y/N): "
     read -r response