diff --git a/subiquity/server/controllers/install.py b/subiquity/server/controllers/install.py
index 73bc09d3a..21b292e19 100644
--- a/subiquity/server/controllers/install.py
+++ b/subiquity/server/controllers/install.py
@@ -226,7 +226,8 @@ async def get_target_packages(self, context):
         description="installing {package}")
     async def install_package(self, *, context, package):
         await run_curtin_command(
-            self.app, context, 'system-install', '--', package)
+            self.app, context, 'system-install', '-t', self.tpath(),
+            '--', package)
 
     @with_context(description="restoring apt configuration")
     async def restore_apt_config(self, context):