Hey, I just joined Omnimaga and it looks like a very cool site.

I was just wondering what it means to "unlock flash" I recently encountered one of Brandon Wilson's unlocking flash programs at http://www.brandonw.net/calcstuff/
and i want to know what it does.

Thanks

Thanks and no problem.

I just really started calculator programming and have no idea what all this fancy stuff is. =)

Yeah, I think i'm going to stick with basic for now. There's a lot of interesting stuff at http://www.brandonw.net/calcstuff/. I even heard from one of my friends that you can use a usb drive with the calculator and even listen to music! I don't even understand how that is even possible.

you can even listen to music without usb drive. www.revsoft.org got a program called RealSound to do that. It takes a lot of memory, though, for like 30 seconds of music

TI restricts writing to Flash and reading from the certificate through a locking/unlocking mechanism. To unlock Flash, a special sequence of z80 instructions must be executed from a "privileged page", meaning an area of Flash memory granted unlock access through hardware. It is impossible to change which pages are privileged.

The privileged pages are 1Ch/3Ch/7Ch, 1Dh/3Dh/7Dh, 1Fh/3Fh/7Fh, 2Fh/6Fh (84+ and 84+SE only), and presumably 1Eh/3Eh/7Eh. All of these pages are either OS pages, permanently write-locked boot code pages, or the certificate (non-code pages). Because TI's code is on these pages, we cannot unlock Flash.

Code could be added to the privileged pages to unlock Flash for you, but to write it, you must first unlock Flash.

The only way to do it is to trick the OS or boot code into unlocking it for you, and there are various exploits available to do that. TI does not like this, because it allows you to write to the user archive (potentially destabilizing it), modify or replace the OS, modify or replace the certificate, etc.

Over the years, we've learned a lot about how the calculator works and found stable exploits that either cannot or are unlikely to be patched or fixed by TI, so this isn't as scary as it used to be.

It doesn't directly relate, no. To install a third-party OS, we would have to use a Flash unlocking exploit at some point, yes. Free83P must unlock Flash to modify the certificate, and any oncalc OS receiver must unlock Flash in order to write the received OS to memory.

Cracking the OS signing keys means that we no longer have to resort to any of that trickery. We can simply sign the OS as simply as TI signs their own. You would just transfer it using the cable and software of your choice and it just works (just like the TI-OS). It also means we can make slight modifications to the TI-OS and re-sign it (in theory), which is the main reason why they want to suppress this knowledge.

It will not work. No matter what, TI has lost and we have won, and it's a cause for celebration because it will spark new development for everyone.

I hope no matter what they do, that third party OS installing remains easier for the average calculator programmer. By that, I mean that the user will not have to search hours for a torrent containing the keys and that forum users will not need to keep LMGTFY people even more.

For sure, though, new doors are opened, still, for TI calc developpement.

I'm not sure anyone has started modifying the TI-OS, but we shouldn't promote that kind of discussion publicly as it is most definitely illegal in every sense of the word. (Also, we've been patching and modifying the TI-OS for years, long before any of this.)

Third party OS installation has never before been this easy; you just transfer it the same exact way you would the TI-OS. That's the beauty of it.
The TI-73 freeware Flash application key has also been cracked, making it possible to create TI-73 Flash applications that work just like 83+ ones do.