Update external_fuzzing_usb.md
diff --git a/docs/linux/external_fuzzing_usb.md b/docs/linux/external_fuzzing_usb.md
index 580a071..904c077 100644
--- a/docs/linux/external_fuzzing_usb.md
+++ b/docs/linux/external_fuzzing_usb.md
@@ -36,7 +36,9 @@
6. Enable `syz_usb_connect` and `syz_usb_disconnect` syscalls in the manager config.
-7. Run.
+7. Set `sandbox` to `none` and `procs` to `1` in the manager config.
+
+8. Run.
Syzkaller descriptions for USB fuzzing can be found here: [1](/sys/linux/vusb.txt) and [2](/sys/linux/vusb_ids.txt).
