Use dd for 'asis' reads

sat

@@ -567,7 +567,7 @@ fi
 export GPG_TTY=$(tty)
 queue=""
 if [ "$mode" == "asis" ]; then
-  queue+="cat \"$in_file\""
+  queue+="dd if=\"$in_file\" bs=1M iflag=fullblock"
   
   ########################################
   # Progress
@@ -629,6 +629,7 @@ elif [ "$mode" == "backup" ]; then
   this_stage=3
   if ((this_stage + 1 == target_stage)); then
     queue+=" | dd bs=1M iflag=fullblock of=\"$out_file\""
+
   else
     if $checksum; then
       if $hex; then