<s>
Xbox	B-Device
modding	I-Device
is	O
the	O
practice	O
of	O
circumventing	O
the	O
built-in	O
hardware	O
and	O
software	O
security	O
mechanisms	O
of	O
the	O
Xbox	B-Application
video	O
game	O
console	O
.	O
</s>
<s>
The	O
popularity	O
of	O
the	O
Xbox	B-Application
,	O
as	O
well	O
as	O
(	O
in	O
the	O
United	O
States	O
)	O
its	O
comparatively	O
short	O
90-day	O
warranty	O
,	O
inspired	O
efforts	O
to	O
circumvent	O
the	O
built-in	O
hardware	O
and	O
software	O
security	O
mechanisms	O
,	O
a	O
practice	O
known	O
as	O
"	O
cracking	O
"	O
.	O
</s>
<s>
Within	O
a	O
few	O
months	O
of	O
its	O
release	O
the	O
initial	O
layer	O
of	O
security	O
on	O
the	O
Xbox	B-Application
BIOS	O
(	O
which	O
relied	O
heavily	O
on	O
obfuscation	O
)	O
was	O
broken	O
by	O
MIT	O
student	O
Andrew	O
Huang	O
and	O
the	O
contents	O
of	O
the	O
"	O
hidden	O
"	O
boot	O
ROM	O
embedded	O
on	O
the	O
MCPx	O
chip	O
were	O
extracted	O
using	O
some	O
custom	O
built	O
hardware	O
.	O
</s>
<s>
Once	O
this	O
information	O
was	O
available	O
,	O
the	O
code	O
was	O
soon	O
modified	O
so	O
that	O
it	O
would	O
skip	O
digital	O
signature	O
checks	O
and	O
media	O
flags	O
,	O
allowing	O
unsigned	O
code	O
,	O
Xbox	B-Application
game	O
backups	O
,	O
etc.	O
,	O
to	O
be	O
run	O
.	O
</s>
<s>
All	O
of	O
Microsoft	O
's	O
Xbox	B-Application
prototypes	O
were	O
,	O
in	O
fact	O
,	O
AMD	O
.	O
</s>
<s>
Hackers	O
from	O
the	O
Xbox	B-Application
Linux	B-Application
team	O
checked	O
with	O
AMD	O
employees	O
and	O
explained	O
that	O
AMD	O
chips	O
throw	O
an	O
exception	O
in	O
the	O
case	O
of	O
EIP	O
overflows	O
,	O
but	O
Intel	O
CPU	O
's	O
do	O
not	O
.	O
</s>
<s>
Plenty	O
of	O
Xbox	B-Application
games	O
had	O
buffer	O
vulnerabilities	O
in	O
their	O
savegame	O
handlers	O
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
use	O
most	O
USB	O
sticks	O
with	O
the	O
Xbox	B-Application
,	O
and	O
just	O
store	O
hacked	O
savegames	O
on	O
them	O
.	O
</s>
<s>
The	O
procedure	O
for	O
the	O
user	O
was	O
then	O
to	O
simply	O
copy	O
a	O
hacked	O
savegame	O
from	O
a	O
USB	O
stick	O
onto	O
the	O
Xbox	B-Application
hard	O
disk	O
,	O
run	O
the	O
game	O
and	O
load	O
the	O
save-game	O
.	O
</s>
<s>
But	O
after	O
a	O
buffer	O
exploit	O
,	O
we	O
would	O
expect	O
only	O
to	O
be	O
in	O
user	O
mode	O
-	O
but	O
not	O
on	O
the	O
Xbox	B-Application
,	O
as	O
all	O
Xbox	B-Application
games	O
run	O
in	O
kernel	O
mode	O
.	O
</s>
<s>
Now	O
every	O
time	O
the	O
Xbox	B-Application
is	O
turned	O
on	O
,	O
the	O
Dashboard	O
crashes	O
because	O
of	O
the	O
fonts	O
and	O
runs	O
code	O
embedded	O
in	O
these	O
files	O
.	O
</s>
<s>
Modding	O
an	O
Xbox	B-Application
in	O
any	O
manner	O
will	O
void	O
its	O
warranty	O
,	O
as	O
it	O
may	O
require	O
disassembly	O
of	O
the	O
console	O
.	O
</s>
<s>
Having	O
a	O
modified	O
Xbox	B-Application
may	O
also	O
disallow	O
it	O
from	O
accessing	O
Xbox	B-Application
Live	O
,	O
if	O
detected	O
by	O
Microsoft	O
,	O
as	O
it	O
contravenes	O
the	O
Xbox	B-Application
Live	O
Terms	O
of	O
Use	O
,	O
but	O
most	O
modchips	O
can	O
be	O
disabled	O
,	O
allowing	O
the	O
Xbox	B-Application
to	O
boot	O
in	O
a	O
"	O
stock	O
"	O
configuration	O
.	O
</s>
<s>
Softmods	B-Device
can	O
be	O
disabled	O
by	O
"	O
coldbooting	O
"	O
a	O
game	O
(	O
having	O
the	O
game	O
in	O
the	O
DVD	O
drive	O
before	O
turning	O
the	O
console	O
on	O
,	O
so	O
the	O
softmod	B-Device
is	O
not	O
loaded	O
)	O
or	O
by	O
using	O
a	O
multiboot	O
configuration	O
.	O
</s>
<s>
Modchip	O
:	O
installing	O
a	O
modchip	O
inside	O
the	O
Xbox	B-Application
that	O
bypasses	O
the	O
original	O
BIOS	O
,	O
with	O
a	O
hacked	O
BIOS	O
to	O
circumvent	O
the	O
security	O
mechanisms	O
.	O
</s>
<s>
TSOP	B-Algorithm
flashing	O
:	O
reflashing	O
the	O
onboard	O
BIOS	O
chip	O
with	O
a	O
hacked	O
BIOS	O
to	O
circumvent	O
the	O
security	O
mechanisms	O
.	O
</s>
<s>
The	O
Xbox	B-Application
BIOS	O
is	O
contained	O
on	O
a	O
commodity	O
EEPROM	B-General_Concept
(	O
the	O
'	O
TSOP	B-Algorithm
 '	O
)	O
,	O
which	O
can	O
be	O
made	O
writable	O
by	O
the	O
Xbox	B-Application
by	O
bridging	O
points	O
on	O
the	O
motherboard	O
.	O
</s>
<s>
Flashing	O
is	O
usually	O
carried	O
out	O
by	O
using	O
a	O
specially	O
crafted	O
gamesave	O
(	O
see	O
'	O
Game	O
save	O
exploit	O
 '	O
,	O
below	O
)	O
to	O
flash	O
the	O
onboard	O
TSOP	B-Algorithm
,	O
but	O
the	O
TSOP	B-Algorithm
can	O
also	O
be	O
de-soldered	O
and	O
re-written	O
in	O
a	O
standard	O
EEPROM	B-General_Concept
programmer	O
.	O
</s>
<s>
This	O
method	O
only	O
works	O
on	O
1.0	O
to	O
1.5	O
Xboxes	B-Application
,	O
as	O
version	O
1.6	O
(	O
the	O
final	O
hardware	O
version	O
produced	O
)	O
replaced	O
the	O
commodity	O
TSOP	B-Algorithm
with	O
an	O
LPC	O
ROM	O
contained	O
within	O
a	O
proprietary	O
chip	O
.	O
</s>
<s>
Softmods	B-Device
:	O
installing	O
additional	O
software	O
files	O
to	O
the	O
Xbox	B-Application
hard	O
drive	O
,	O
which	O
exploit	O
programming	O
errors	O
in	O
the	O
Dashboard	O
to	O
gain	O
control	O
of	O
the	O
system	O
,	O
and	O
overwrite	O
the	O
in-memory	O
copy	O
of	O
the	O
BIOS	O
.	O
</s>
<s>
Soft	O
modification	O
is	O
known	O
to	O
be	O
safe	O
for	O
Xbox	B-Application
Live	O
if	O
the	O
user	O
enables	O
multibooting	O
with	O
the	O
Microsoft	O
dashboard	O
and	O
an	O
original	O
game	O
disc	O
is	O
used	O
.	O
</s>
<s>
When	O
these	O
special	O
game	O
saves	O
are	O
loaded	O
,	O
they	O
access	O
an	O
interface	O
with	O
scripts	O
for	O
installing	O
the	O
necessary	O
softmod	B-Device
files	O
.	O
</s>
<s>
Disassembly	O
of	O
the	O
Xbox	B-Application
is	O
not	O
required	O
when	O
installing	O
most	O
game	O
save	O
exploits	O
.	O
</s>
<s>
Hot	B-Device
swapping	I-Device
:	O
using	O
a	O
computer	O
to	O
change	O
the	O
data	O
on	O
the	O
hard	O
drive	O
.	O
</s>
<s>
This	O
requires	O
having	O
the	O
Xbox	B-Application
unlock	O
the	O
hard	O
drive	O
when	O
it	O
is	O
turned	O
on	O
,	O
then	O
swapping	O
the	O
powered	O
hard	O
drive	O
into	O
a	O
running	O
computer	O
.	O
</s>
<s>
By	O
using	O
a	O
Linux-based	O
Live	O
CD	O
,	O
data	O
on	O
the	O
hard	O
drive	O
can	O
be	O
read	O
,	O
altered	O
,	O
and	O
deleted	O
.	O
</s>
<s>
In	O
most	O
cases	O
,	O
an	O
automated	O
script	O
will	O
automatically	O
install	O
the	O
softmod	B-Device
files	O
directly	O
to	O
the	O
Xbox	B-Application
hard	O
drive	O
.	O
</s>
<s>
Disassembly	O
of	O
the	O
console	O
is	O
required	O
to	O
perform	O
a	O
hot	B-Device
swap	I-Device
.	O
</s>
<s>
It	O
's	O
the	O
least	O
recommended	O
as	O
it	O
might	O
shock	O
the	O
Xbox	B-Application
hardware	O
or	O
the	O
user	O
's	O
PC	O
components	O
.	O
</s>
<s>
Beyond	O
gaming	O
,	O
a	O
modded	B-Device
Xbox	I-Device
can	O
be	O
used	O
as	O
a	O
media	O
center	O
with	O
XBMC4Xbox	B-Language
.	O
</s>
<s>
There	O
are	O
also	O
distributions	O
of	O
Linux	B-Application
developed	O
specifically	O
for	O
the	O
Xbox	B-Application
,	O
including	O
those	O
based	O
on	O
Gentoo	B-Application
,	O
Debian	O
,	O
Damn	B-Operating_System
Small	I-Operating_System
Linux	I-Operating_System
and	O
Dyne:bolic	B-Application
.	O
</s>
<s>
Xbox	B-Application
Linux	B-Application
is	O
a	O
project	O
that	O
ported	O
Linux	B-Application
to	O
the	O
Xbox	B-Application
.	O
</s>
<s>
FreeBSD	B-Operating_System
and	O
NetBSD	B-Device
have	O
also	O
been	O
ported	O
to	O
Xbox	B-Application
.	O
</s>
<s>
A	O
port	O
of	O
Windows	B-Application
XP	I-Application
for	O
the	O
Xbox	B-Application
is	O
available	O
on	O
some	O
modding	O
websites	O
,	O
however	O
the	O
installation	O
of	O
this	O
usually	O
involves	O
desoldering	O
the	O
stock	O
CPU	O
and	O
replacing	O
it	O
with	O
a	O
different	O
Pentium	B-General_Concept
III	I-General_Concept
CPU	O
(	O
in	O
mobile	O
form-factor	O
)	O
,	O
as	O
well	O
as	O
a	O
heavily	O
modified	O
BIOS	O
.	O
</s>
