<form method="post" action="/cgi-bin/luci/;stok=4DB4115975EF48FD742227BAD3580034/engineer/advanced/diagnostics/upgrade" enctype="multipart/form-data"></p>

Note: there is a cache generated after login as follows: 
Set-Cookie: sysauth=ACA415DA69DD4170D34D2DDCE2B610F5; path=/cgi-bin/luci/;stok=44F89C9B8E1EB34F9D379B5162763EAF

Location: /cgi-bin/luci/;stok=44F89C9B8E1EB34F9D379B5162763EAF/engineer
So I need to use the token when doing the upload.
The source is follow by "zentaras" 
<code>#!/usr/bin/perl
use warnings;
use strict;
use LWP::UserAgent;
use HTTP::Cookies;
use HTTP::Request::Common qw(POST);

#test on plain http

my $http_post = 'http://192.168.1.1/cgi-bin/luci/engineer/advanced/diagnostics/upgrade/';
my $http_user = 'engineer';
my $http_pass = 'ARC$eng&123';
my $file = 'rev1-54.zip';


&postHTTP();

sub postHTTP
{
        my $ua = new LWP::UserAgent;
        $ua->protocols_allowed( [ 'http'] );
        $ua->cookie_jar(HTTP::Cookies->new(file =>".cookies.txt",autosave => 1));

  #setup request
        my $req = POST($http_post, 
	        Content_Type => 'multipart/form-data',
	        
	        Content =>[        	
		           file =>[ $file  ],
        		  ], );

         my $user = 'engineer';
         my $pass = 'ARC$eng&123';
         $req->authorization_basic($user, $pass);

  #do post         
	 my $response = $ua->request($req);
	 if ($response->is_error())
        	{
        	        printf " %s\n", $response->status_line;
        	        print "http request error!\n";
        	} else {
        	        my $content = $response->content();
        	        print "$content\n";
		        }

         if ( $response->is_success ) {
                   print $response->as_string;
         }else {
               print $response->status_line;
         }

}