diff --git a/bootstrap.py b/bootstrap.py
index 0f8dc9ef588..15ed60ca70b 100755
--- a/bootstrap.py
+++ b/bootstrap.py
@@ -86,7 +86,7 @@
         prev_branch = boot_branch_file.read_text()
 
     result = subprocess.run(
-        ["git", "merge-base", "--fork-point", "master"],
+        ["git", "-C", DEVPATH, "merge-base", "--fork-point", "master"],
         capture_output=True
     )
     branch = "master" if result.stdout else "not master"