diff --git a/99-usb-sync.rules b/99-usb-sync.rules
index 85f0116..f44cb35 100644
--- a/99-usb-sync.rules
+++ b/99-usb-sync.rules
@@ -1,6 +1,6 @@
 # rule to disable write cache for usb storage
 # requires hdparm to be installed
-ACTION=="add|change", KERNEL=="sd[a-z]", ENV{ID_USB_TYPE}=="disk", RUN+="[[ $(uname -r | awk -F'.' '{print $1 $2}') < 62 ]] && /usr/bin/hdparm -W 0 /dev/%K"
+ACTION=="add|change", KERNEL=="sd[a-z]", ENV{ID_USB_TYPE}=="disk", RUN+="[[ $(uname -r | awk -F'.' '{print $1 $2}') < 62 ]] && [[ $(which hdparm) =~ (hdparm) ]] && && /usr/bin/hdparm -W 0 /dev/%K"
 #
 # rules to impose buffer limits on USB devices
 # requires kernel > 6.1