Mtv Europe

IOS repacking

Sun, 13 Dec 2009 18:22:04 GMT

"mz" IOSes can be squeezed using 7zip compression, which is compatible with ZIP format and has better ratio. Typically it's 3-5% reduction of file size.

Caution: this technique violates legal rights and reduces flash memory sales.

I've used this hack for many years and different platforms, it always worked since it touches only the boot phase and if you've booted you're already ok.

Let's do the trick step by step, for example with c1600-sy-mz.122-46a.bin size 4'285'105 that is slightly bigger then 4 MB = 4'194'304 bytes.

Split original binary on two parts, loader and archive. Archive part starts with usual "PK" magic bytes so in our case the loader is 10'540 bytes, and unpacked C1600-SY.BIN is 9'320'776 bytes.

Repack BIN with 7zip "ultimate" "deflate" compression, that will give 4'136'458 bytes instead of original size 4'274'565.

Fix headers in loader, one number is at offset 8 from the beginning and another is at -12 from the end. There is also a checksum at -8 from the end but it's easier to let router to calculate it instead of guessing it by yourself.

So concatenate fixed loader and repacked archive, try to boot and you will get something like

Error : compressed image checksum is incorrect 0xF7975E88
        Expected a checksum of 0x6C794F36

Fix those numbers too and voila:

c1601#sh ver | i IOS|flash
IOS (tm) 1600 Software (C1600-SY-M), Version 12.2(46a), RELEASE SOFTWARE (fc1)
System image file is "flash:c1600-sy-mz.122-46a-mtve.bin"
4096K bytes of processor board PCMCIA flash (Read/Write)

c1601#dir
Directory of flash:/

    1  -rw-     4146998                    <no date>  c1600-sy-mz.122-46a-mtve.bin

4194300 bytes total (47236 bytes free)

Better compression (25-30%) could be achieved with LZMA algorithm of 7z but it requires porting and compiling of decompression code to target platform.

Fri, 09 Oct 2009 12:15:05 GMT

it's for google again, brave new powerful word "configipin"

Tue, 22 Sep 2009 19:31:20 GMT

These java programs are the best:

What would you recommend to add to this list?

Mon, 21 Sep 2009 15:31:45 GMT

DBD::CSV rocks, it can work in pure perl:

#!/usr/bin/perl -w

use strict;
use warnings;

use lib 'lib';

BEGIN { $ENV{DBI_PUREPERL} = 2; } use DBI;
use Text::CSV_PP; *Text::CSV_XS::=\%Text::CSV_PP::; $INC{'Text/CSV_XS.pm'}++;
use Clone::PP; BEGIN { *SQL::Statement::clone=\&Clone::PP::clone; }
$INC{'Clone.pm'}++;

my $dbh = DBI->connect("DBI:CSV:f_dir=db", "", "", { RaiseError => 1 });

for my $sql (split /;/, "
     CREATE TABLE user ( user_name TEXT, phone TEXT );
     INSERT INTO user VALUES ('Fred Bloggs','233-7777');
     INSERT INTO user VALUES ('Sanjay Patel','777-3333');
     INSERT INTO user VALUES ('Junk','xxx-xxxx');
     DELETE FROM user WHERE user_name = 'Junk';
     UPDATE user SET phone = '999-4444' WHERE user_name = 'Sanjay Patel';
     SELECT * FROM user ORDER BY user_name
"){
	next if $sql =~ /^\s*#/;

	my $sth = $dbh->prepare ($sql);
	$sth->execute;
	$sth->dump_results if $sth->{NUM_OF_FIELDS};
}

requirements:

Clone-PP
DBD-CSV
DBI
Params-Util
SQL-Statement
Text-CSV

Wed, 12 Aug 2009 10:54:08 GMT

f*cking f*ck, "positive integer constant list"

Wed, 15 Jul 2009 20:28:40 GMT

Nice trick and nice language (via LtU)

Mon, 11 May 2009 08:52:03 GMT

Ulticom Signalware & World of Warcraft

Fri, 27 Mar 2009 07:26:37 GMT

http://arxiv.org/abs/0903.4299 - wtf?

Thu, 19 Feb 2009 17:37:37 GMT

Nice math pictures (via The Reference Frame blog)

Thu, 05 Feb 2009 18:45:27 GMT

Primus is the only band to have their own ID3 genre tag in Winamp, yesss!

Fri, 30 Jan 2009 19:14:51 GMT

I guess I should post something, just to laugh over myself.

Here is a screenshot of my desktop taken more then 10 years ago, at April 13th of 1998:

Sat, 30 Aug 2008 16:07:52 GMT

Sun, 24 Aug 2008 18:37:48 GMT

Fri, 04 Jul 2008 19:40:10 GMT

KB done, it was great.

Two quite simple and sensible words that are no exist in google yet - XmtFELOF and RcvFELOF.

New friends, I really appreciate it.

One superb math talk "Pitfalls in Computation: Random and not so Random Numbers".

Io programming language (by sdfgh153)

Games

Thu, 12 Jun 2008 12:15:31 GMT

Simon the Sorcerer 3D, ZanZarah: The Hidden Portal, and *** King's Bounty. Легенда о Рыцаре ***

Mood: Эффект не действует на войска с иммунитетом к Разуму

Games

Thu, 29 May 2008 20:04:49 GMT

Portal, Defcon, Tribal Trouble

Sat, 17 May 2008 09:07:23 GMT

I've got new toy Geomag.

Picture is not mine:

Wed, 16 Apr 2008 18:00:29 GMT

AT&T Labs Research regex(3) regression tests (via проФорт blog)

the must read

Wed, 16 Apr 2008 17:57:47 GMT

arXiv:0804.0032v1 "The brain: What is critical about it?" by Dante R. Chialvo, Pablo Balenzuela, Daniel Fraiman

nice book

Wed, 16 Apr 2008 17:50:40 GMT

"Riding Rockets: The Outrageous Tales of a Space Shuttle Astronaut" by Mike Mullane

(via Вселенная Пространство Время magazine)

Wed, 02 Apr 2008 20:07:26 GMT

V7/x86!

Wed, 02 Apr 2008 20:05:24 GMT

raid5 saga (1, 2) continues - one more disk has died.

new ad6 238475MB "WDC WD2500JB-00REA0" for $70

update: following crash:

Apr  3 03:24:42 heart /kernel: vinum: raid5.p0.s2 is up by force

shortly after

panicstr: integer divide fault
panic messages:
---
Fatal trap 18: integer divide fault while in kernel mode
instruction pointer     = 0x8:0xc02fbfae
stack pointer           = 0x10:0xca842c5c
frame pointer           = 0x10:0xca842cc8
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 16 (vinum)
interrupt mask          = none
trap number             = 18

with backtrace:

#0  0xc01747fa in dumpsys ()
#1  0xc01745c4 in boot ()
#2  0xc01749f8 in poweroff_wait ()
#3  0xc02ea5bf in trap_fatal ()
#4  0xc02e9f83 in trap ()
#5  0xc02fbfae in __qdivrem ()
#6  0xc02fbe83 in __divdi3 ()
#7  0xc23e2f17 in ?? ()
#8  0xc23e3757 in ?? ()
#9  0xc23e17bf in ?? ()
#10 0xc23e19ba in ?? ()
#11 0xc23e461d in ?? ()
#12 0xc01af240 in spec_ioctl ()
#13 0xc01aef51 in spec_vnoperate ()
#14 0xc02795c1 in ufs_vnoperatespec ()
#15 0xc01ab76f in vn_ioctl ()
#16 0xc0184536 in ioctl ()
#17 0xc02ea879 in syscall2 ()
#18 0xc02de195 in Xint0x80_syscall ()
Cannot access memory at address 0xbfbffd10.

Sun, 17 Feb 2008 09:15:31 GMT

SCC5: POVRay Short Code Contest #5 (via /.)

Thu, 14 Feb 2008 12:28:39 GMT

Benoit Mandelbrot Fractal Art Contest 2007! (via MathPuzzle.com)

Fri, 21 Dec 2007 17:47:57 GMT

Traffic on my home main connection (since this).