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Messages - BrandonW
106
« on: August 30, 2009, 11:34:07 pm »
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.
107
« on: August 30, 2009, 05:47:36 pm »
The video is most definitely fake, however it is not impossible to get into an XP user account using only your 84+/SE.
You can write a Flash application which simulates a USB flash drive and a boot floppy image (a special one containing one of those "reset the XP Administrator accounts" bootable floppy disks that are available on the internet) and connect it to your computer via direct USB.
From there, your computer could boot off the calculator and you could run the program from the "floppy". That would let you reset the administrator account.
From there, you can simply log onto the XP Administrator account, or you could use another Flash application which simulates a USB keyboard and have it "press" the necessary keys to log in.
These Flash applications are certainly possible and I started work on it some time ago, called periph8x. It can make the calculator show up as a USB flash drive or USB keyboard. Unfortunately, what I never got to work was booting off the calculator. USB initialization seems to work differently when booting from the device as opposed to being in Windows, and I never solved that problem. But if I had, then yes, this is certainly possible (this video was partially my motivation for attempting it).
108
« on: August 30, 2009, 05:42:22 pm »
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.
109
« on: May 22, 2009, 04:39:21 am »
I would be willing to pay whatever it takes to get it here, whenever one shows up.
Is it documented anywhere what the exact technical differences are between the TI-83 and TI-82 Stats (meaning, the differences between ROM versions 1.10 and 1.11)?
110
« on: May 21, 2009, 08:05:07 pm »
I'm very interested in buying this calculator, but I'm in the US. Is there a web site I could buy this from that ships to the United States, or could one of you who possibly lives in Europe help me in securing one?
EDIT: I'd also just be happy with a ROM dump if one of you already has it (and if it will let you dump it).
111
« on: November 15, 2007, 05:33:00 am »
QuoteBegin-DJ Omnimaga+14 Nov, 2007, 15:56--> | QUOTE (DJ Omnimaga @ 14 Nov, 2007, 15:56) | | really? I tried this back then with my bro calc and it wouldnt accept the transfer, maybe they allowed it in later versions, since I had OS 1.12 back then |
When you use [ON]+[DEL], you're telling the boot code to take control and receive a new OS. The boot code isn't upgradeable, so something else must've been going on.
112
« on: October 23, 2007, 06:01:00 pm »
QuoteBegin-DJ Omnimaga+23 Oct, 2007, 23:42--> | QUOTE (DJ Omnimaga @ 23 Oct, 2007, 23:42) | haha yeah this is kinda contradictory to the usual %) but he has a good point tho
btw is there anyone who ever managed to get a TI-73 OS to run on a 83+ or vice versa? Or a 84+ OS on a 83+SE or vice versa for that matter? |
You can put the 73 OS on an 83+ and the 83+ OS on a 73. Lots of people have put the 73 OS on an 83+ before...as far as the latter... http://brandonw.net/calcstuff/73.wmv. Off the top of my head, I don't see why the 84+/SE OS can't run on an 83+SE, but I don't have one so I can't test.
113
« on: October 23, 2007, 05:34:00 pm »
QuoteBegin-Jon+23 Oct, 2007, 23:31--> | QUOTE (Jon @ 23 Oct, 2007, 23:31) | | cuz it's the SE and they were just too lazy to edit the TIOS to utilize those pages. the 84+(SE) OS is almost identical to the 83+(SE) OS with the exception of USB code and some minor revisions. The OS was designed to be universal, which is why it checks bit 7 of port 2 in alot of its routines. (that bit is reset for 83+ BE, set for everything else) |
More like TI was too lazy to remove the "if 83+BE, do this, otherwise do that" checks from the 84+/SE OS, and the 83+SE has no use (at the moment) for the extra RAM pages (in TI's view). It's there for future expansion, nothing else. USB later ended up being the expansion.
They can't change how the VAT's page byte works because that would break everyone's 83+ code, and they strive for compatibility between all four calculators.
114
« on: October 23, 2007, 04:49:00 pm »
QuoteBegin-Super Speler+12 Apr, 2007, 16:41--> | QUOTE (Super Speler @ 12 Apr, 2007, 16:41) | | How safe (or un-safe) would this be to use? |
Lots of other programs (Virtual Calc, Omnicalc, msd8x, probably others) will use this RAM as scratch space, so that would mean your data is corrupted when you try to get those variables back. You can check to make sure your data's valid, but not recover it.
But if you know you don't use those, then you're safe.
The OS also doesn't touch these RAM pages when the calculator resets, so it's a good way of keeping RAM variables after reset, too.
115
« on: October 13, 2006, 03:29:00 pm »
http://www.ticalc.org/archives/files/fileinfo/247/24750.htmlThis is everything you want and more. The header is the same with all files, 8XI, 8XP, etc. The data after the header is the 756 bytes of pixel data. 12 bytes per row, 8 pixels per byte (naturally). (12*8*64)-12=756, starting from the top left of the screen. The -12 comes from the fact that the bottom row is not stored. One problem with the guide, though, is that it documents 0Dh as being a fixed byte...this isn't true, it's actually the size of the header to follow. Sometimes this is 0Bh and maybe others.
116
« on: October 11, 2006, 04:54:00 am »
| QUOTE | | IDEA! Usb8x/Msd8x(even though MSD8x is just a frontend and USB8x has the driver in it) |
Precisely. You could use the assembly interface (or even the BASIC one) at usb8x.denglend.net to add support for files off a flash drive. It's as simple as opening the file and reading and seeking wherever and whenever you want.
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