Create perl file (unstash.pl) and run the script.
#!/usr/bin/perl
#usage perl unstash.pl
use strict;
die "Usage: $0 \n" if $#ARGV != 0;
my $file=$ARGV[0];
open(F,$file) || die "Can't open $file: $!";
my $stash;
read F,$stash,1024;
my @unstash=map { $_^0xf5 } unpack("C*",$stash);
foreach my $c (@unstash) {
last if $c eq 0;
printf "%c",$c;
}