diff --git a/src/yunohost/app.py b/src/yunohost/app.py
index 93ffbbb5b..686209225 100644
--- a/src/yunohost/app.py
+++ b/src/yunohost/app.py
@@ -2761,7 +2761,7 @@ def _make_environment_for_app_script(app, args={}, args_prefix="APP_ARG_"):
     }
 
     for arg_name, arg_value_and_type in args.items():
-        env_dict["YNH_%s%s" % (args_prefix, arg_name.upper())] = arg_value_and_type[0]
+        env_dict["YNH_%s%s" % (args_prefix, arg_name.upper())] = str(arg_value_and_type[0])
 
     return env_dict
 
diff --git a/src/yunohost/hook.py b/src/yunohost/hook.py
index 1758a1167..53ed5f2e5 100644
--- a/src/yunohost/hook.py
+++ b/src/yunohost/hook.py
@@ -391,7 +391,7 @@ def _hook_exec_bash(path, args, chdir, env, return_format, loggers):
     env['YNH_STDRETURN'] = stdreturn
 
     # use xtrace on fd 7 which is redirected to stdout
-    env['BASH_XTRACEFD'] = 7
+    env['BASH_XTRACEFD'] = "7"
     cmd = '/bin/bash -x "{script}" {args} 7>&1'
     cmd = cmd.format(script=cmd_script, args=cmd_args)