A first method is to patch King Kong with altered shader, but copying a game is not a so clean solution...

But thanks to timing attack project, a subpart of console (if it's a recent model) is quite under control inside a little time window at boot time. Seventhson and tmbinc finally made some significant progress (yesterday).
Nothing complete yet, but some new understanding opened new ways of messing up with old consoles...

http://www.xboxhacker.net/index.php?topic=9230.20

Don't post there if you are not a 'master hacker' able to test that stuff .
For example, if you don't know what SMC or JTAG is, you are not one...
And no need to ask about recent consoles, it's out of the question.

EDIT: Yeah!!! Ask about recent consoles!
model<jasper and kernel version<849x -summer 09 update-
or
MFR date<2009-06-18 for model=jasper (CB<6750 required)

one step closer to homebrew

I sense a bit of an elitist attitude, how does one become a master hacker, so that I may be so smug?

Please don't feel offended. I'm not considering myself as a 'master hacker' either.

It's important to warn people that posting in these high level brainstorming threads (on xbh site) will really be considered offending by mods and real contributors there, if your post doesn't contribute (and just asks for explanations).

If you want to ask for anything try this thread (but not sure I will know the answer myself) or general forums.

For this specific topic (messing with 360 boot) you need both software (at kernel level) and electronics skills (since you need to interfere with some electronic signals on the motherboard at boot time).

First step would be to successfully be able to switch 360 firmware at will with soldered infectus, then try to discover cpu key (for fun, since you have it already, logically) using your own designed device (so you can modify it and see if you can follow up the current existing sample that turn leds to orange at boot time. not my case yet).

Well, I am a little bit confused about this, they found out stuff on "recent model",and can control "recent model" during boot time? To my knowledge, isn't the time attack stuff only work on the old model? You mean they finally made a progress to bring the final model down?
Please kindly give me some explain
Else: I can't view the topic you pasted here, and i'm not a master hacker, so I don't want to register on the xboxhacker.net, so would you give some detail on that thing?thanks..

I wrote :
"And no need to ask about recent consoles, it's out of the question."

That means all this applies only to older consoles (the ones that can already use KK method)

This research purpose is just to get rid of patched KK backup requirement

EDIT:
no longer valid. zephyr, falcon now hacked. just avoid last kernel updates and get a 360 with a manufacture date before june 2009.

Ok, the "Incredibles" hackers at xbh made it again! Alternate homebrew activation done, even on Jasper!
Many thanks to : tmbinc, Robinsod, SeventhSon, Martin_sw and Tiros.

Personally I think we all should focus on Jasper. But we need Jasper's with kernel<849x (summer 09 update), so it's really a race now to grab massively these machines from the shelves and deliver them to professional modders.

Yes, pros, because the modding is a bit far from noobs abilities...
(but don't declare yourself modder in US/UK ok? It's not worthy to risk your freedom. Declare yourself modder or look for modders in countries where modding is legal. Even if this mod is for Linux, cops won't understand)

So, be aware that the result of the modding is a 360 reserved for instant Linux booting.
No more games on it. Because all new games will have, at minimum, the mandatory summer 09 update on them.

The best plan now is to catch a jasper with kernel<849x for linux, and wait for natal for games.

Of course older models can be used but unless they are watercooled they won't survive long...
The jasper has 60nm cpu and gpu thus heats much less than other models.
(only way to recognize them is "12.1 Ampere")

Good hunting to all!

(files and details about specific hardware needed for jasper modding will be released in future. not released yet. but catch jasper now)

It seems that the green arcade box, if hdmi and 256Mo MU integrated inside console is mentioned, is a Jasper. Just checked one and it shows 12.1 A at the rear side of the console. Maybe its price (around 200 euros) can still go down soon, since PS3 price just went down. Kernel was 7363. 322Mo free space left (probably 256+what is left in the primary flash). 1 wireless joypad, and no hdmi cable (only scart).

EDIT :
Ok, tmbinc revealed that jtag hack has been fixed in recent Jasper models :

http://www.xboxhacker.net/index.php?topic=12241.0

New condition is CB<6750

That means :

kernel<849x (summer 09 update) for model<jasper
or
MFR date<2009-06-18 for model=jasper (CB<6750 required)

It will be necessary to create a daemon running on 360's Linux in order to continuously monitor the chipsets temperature and adapt the fan speed accordingly

EDIT:
... or not.
New tips posted on xbh by tmbinc reveal that in 1000-4000 range of nand the SMC code (consider it as 8051 coprocessor) may be the one in charge of handling fan speed vs temperature function. So if SMC is correct and fan part is preserved, all should be ok.

I've seen posts of people ruining SMC and reporting loud fan speed on boot, and normal speed once SMC code is repaired. RedLine99 posted also hints about how to disassemble and understand SMC code. That will surely help to understand how it works.

Just repeating here this important news (because 8498 blocks jtag hack) :

Cars Race o Rama is first 'Wave 4' disc
Cars Race o Rama seems to be the first Xbox 360 game with the 'Wave 4'. Basically, Wave 4 is Wave 3 with the new 8498 NXE update.

Feel free to report other retail game names that will kill Jtag hack when you update kernel
(because it doesn't update the kernel only...)

(hmm just dreaming : what would MS position would become, in regard of homebrew, if players stopped purchasing games with mandatory homebrew killing updates on them...)