where to get this OS DOWNLOADER?

As SirCmpwn said, it comes with TI Connect. You can get to it from your Start menu under TI Connect.

On TI-BANK, the news about Flashy says something implying they don,t believe we permanently unlocked the 84+ with Flashy, in reference to how they countered the key factoring, Nleash, etc, and that they might try to come with another alternative to prove us wrong. However, I am wondering what kind of alternative they could find...

While it's true that TI can always do something to counter what we do, the fact remains that every 73/83+ and 84+ series calculator manufactured to date (and so far, still being manufactured) is permanently hackable. The only move they have is to modify the hardware, and if you've already bought it, you're in good shape.

To add some more information:

The main uses for this are:
   1. Testing code very early in the boot process. We can learn a lot more about the hardware now that we can get control very early in the boot process (the very first instruction executed!), and we've learned quite a bit in the past week or so.
   2. Downgrading boot code 1.03 calculators, such as the TI-84 Pocket.fr (and now the 84+ and 84+SE, which have started showing up with 1.03). I have upgraded my calculators to 1.03 and downgraded them back to 1.00/1.02 without incident. This means the anti-downrgade protection and added 2048-bit RSA key is useless (epic fail).
   3. Customizing the boot sectors. We can now add Calcsys-like functionality to normally read-only boot sectors and gain new emergency recovery abilities you wish you had in the past. Corrupted OS and you really need to get your programs off? Now you can (as soon as we write such a utility to flash to it). We can also change functionality we assume will always be there -- we can change (and I have changed) the ON+DEL keyboard shortcut to something secret or more complex (to prevent strangers from getting into your calculator), or whatever you want...sky's the limit.

Also, if the process to create the image AppVar looks a little scary/confusing to you, you can use the pre-built AppVars made from boot code dumps available elsewhere (for the 83+SE, 84+, and 84+SE, from versions 1.00 to 1.03). I'd link you to them, but it's not exactly legal to host them. I'm sure if you look around in the "usual places", you can find them.

This program tries to be as safe as possible. The boot image AppVars it uses have up to two MD5 hashes embedded with them, one for each page. Both of these hashes are checked twice, battery levels are checked twice, the images themselves are checked for code patterns that must be present for the model being flashed to, the boot page jump table is checked for valid page and address ranges, and warnings are thrown up if anything looks amiss.

It even installs a temporary cursor hook to steal back control in the unlikely event that the boot page is erased (filled with 0xFF bytes (which are interpreted as "rst 38h" instructions)), where it will attempt to complete the write.

I personally tested it on my real 83+SE, 84+, and 84+SE calculators, and several other people have used it multiple times without incident. I have yet to brick a calculator using this program, even after making some pretty scary patches.

So it's worth a shot, if you're brave enough.

They certainly have to change things in the ASIC so that the port we're modifying no longer has any effect. How difficult that would be is unknown. Based on the fact that they put such bone-headed functionality in there, it's possible it's not that easy.

Even if they did fix it, there are still numerous boot code exploits to get an OS on there, and it appears they made some pretty crappy attempts to block some other hacks.

I hope you're reading this, TI: you have truly failed. The harder you try, the worse you make it on yourself.

They're the same. I think singapore is the code name for the OS.

False. The codename for the 83+ series OS is "Cerberus." You can still see references to this in ti83plus.inc such as "new apps for Cerberus" (the new "external" applications (Flash applications)).

And as stated, the "Singapore" reset leaves a couple more Flash applications intact on reset.

Brandon Wilson recently managed to get Linky (http://brandonw.net/svn/calcstuff/Linky/) to the point that you can emulate a USB flash drive using the TI-89 Titanium and a raw image of sectors you supply.

He packaged the program, the image for the NT Offline Password and Registry Editor boot disc, and the PC program to create TI-89 Titanium Flash applications out of raw sector images at: http://brandonw.net/calcstuff/NTPasswd.zip.

YouTube video showing it:



This same thing could be used to boot DOS or Windows 3.1 as well -- anything known to fit on a floppy disk (or bigger -- there's about 2.3MB to work with).

Hopefully this also gets people more excited about the prospect of a real USB library coming to the TI-89 Titanium, so that it can enjoy all the usb8x goodness that the 84+/SE has.

That's a pretty loaded question and would take a while to answer. At the risk of sounding rude, I would recommend reading the source to see where it puts the signature after it calculates it ("MD5" and "Rabin"/"RSA" are things to look for to find where it calculates the signature and then does something with it).