sprintf "%v02X", $bytes

unpack 'H*', $bytes

##</code><code>##

$ perl -e'
   for my $format (qw( n v )) {
      my $bytes = pack($format, 0x1234);
      CORE::say sprintf "%v02X", $bytes;
      CORE::say unpack "H*", $bytes;
   }
'
12.34
1234
34.12
3412