diff --git a/serial/toml.c b/serial/toml.c
index 5d4d8f6..ee5a894 100644
--- a/serial/toml.c
+++ b/serial/toml.c
@@ -226,8 +226,7 @@ static enum b_status refill_linebuf(struct ctx *ctx)
 		return status;
 	}
 
-	b_string_clear(ctx->ctx_linebuf);
-	status = b_string_append_cstr(ctx->ctx_linebuf, b_stringstream_ptr(buf));
+	status = b_string_replace_all_with_stringstream(ctx->ctx_linebuf, buf);
 	if (!B_OK(status)) {
 		return status;
 	}