Fixed typo that caused error

install.sh

@@ -26,7 +26,7 @@ sudogrp="CHANGEME" # Name of the sudogrp
 CWD="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
 
 while true; do
-    case "$!" in
+    case "$1" in
         -d|--device)
             device="$2"
             shift 2