diff --git a/usbinstall/usbinstall.sh b/usbinstall/usbinstall.sh
index 0072956..cbb5372 100644
--- a/usbinstall/usbinstall.sh
+++ b/usbinstall/usbinstall.sh
@@ -109,9 +109,10 @@ for dev in $devices; do
    native_path=`get_udisks_key $dev native-path`
    vend=`get_udisks_key $dev vendor`
    prod=`get_udisks_key $dev model`
-   [ -e $native_path/partition ] || continue
+   [ -e $native_path/partition ] && continue
    is_system_internal=`get_udisks_key $dev "system internal"`
-   if [ "$is_system_internal" != "1" ]; then
+   partition_scheme=`get_udisks_key $dev "scheme"`
+   if [ "$is_system_internal" != "1" -a "$partition_scheme" = "mbr" ]; then
       c=$((c+1))
       device[$c]=$dev
       vendor[$c]=$vend