diff --git a/usr/libexec/security-misc/check-for-usb-controller#security-misc-shared b/usr/libexec/security-misc/check-for-usb-controller#security-misc-shared
index 515155e..3c00602 100755
--- a/usr/libexec/security-misc/check-for-usb-controller#security-misc-shared
+++ b/usr/libexec/security-misc/check-for-usb-controller#security-misc-shared
@@ -3,9 +3,13 @@
 ## Copyright (C) 2025 - 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
 ## See the file COPYING for copying conditions.
 
+set -e
+
 export LC_ALL='C'
 
 ## Package 'pciutils' provides tool 'lspci'.
+command -v lspci &>/dev/null
+
 if lspci | grep --quiet '^[^ ]* USB controller: '; then
   exit 0
 fi