Author Topic: On-calculator app signing  (Read 21105 times)

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Offline FloppusMaximus

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Re: On-calculator app signing
« Reply #15 on: October 26, 2010, 11:46:34 pm »
Hmm, I wouldn't think so.  What seems to happen in this case is that the app gets compiled as usual, it just gets marked as deleted right away (so it doesn't show up in the apps menu, and as soon as you try to run another app, the OS will start defragmenting.)

Following up... This seems not to be an issue on 84+es at all, and may not be an issue on newer 83+es either.  I don't really know very much about the internals of that part of the OS, and the more I look at it the weirder it gets.  I'm not sure when exactly these status bits are supposed to be set or cleared in normal operation; the one thing I can say for sure is that if the bit is set, the app isn't considered valid and will end up getting deleted.  I think maybe this was an old security measure that TI decided to stop using, or maybe it was never fully implemented to begin with.
« Last Edit: October 27, 2010, 01:32:36 am by FloppusMaximus »

Offline DJ Omnimaga

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Re: On-calculator app signing
« Reply #16 on: October 27, 2010, 01:12:10 am »
Ah ok. I wonder if you might know what might be my problem. People suggest me it might be my flash chip wearing out. This calc was used since 2001 but barely until 2004 (it used to be my bro's calc). What is weird is that I have no problems sending stuff to my archive, same for archiving/unarchiving or during GC.
« Last Edit: October 27, 2010, 01:13:13 am by DJ Omnimaga »

Offline FloppusMaximus

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Re: On-calculator app signing
« Reply #17 on: October 27, 2010, 01:40:09 am »
It is possible, I guess, that you have something weird going on in the certificate page.  If you send me a copy I could take a look - I think BrandonW has tools for backing up and restoring the certificate.

Edit: Yes, he does: http://www.brandonw.net/calcstuff/certtools.zip
« Last Edit: October 27, 2010, 01:41:24 am by FloppusMaximus »

Offline DJ Omnimaga

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Re: On-calculator app signing
« Reply #18 on: October 27, 2010, 01:43:41 am »
Mhmm, the certificate... I haven't thought about that. I'll try to get a dump from mine and send you a copy via e-mail or PM.

EDIT: Hmm it freezes on CERTIMG created ??? (even after a full mem clear). I had to remove a battery, then I got a RAM clear, and no appvar was created.
« Last Edit: October 27, 2010, 01:51:22 am by DJ Omnimaga »

Offline FloppusMaximus

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Re: On-calculator app signing
« Reply #19 on: October 27, 2010, 10:17:41 pm »
Well, that's a pretty straightforward program.  Perhaps it's Brandon's unlocking technique that your calculator doesn't like (I believe Axe uses the same technique.)  You could try this version instead.

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Re: On-calculator app signing
« Reply #20 on: October 27, 2010, 11:05:26 pm »
Cool that one worked fine. I'll send you a copy of my certificate via e-mail. :)

EDIT: Sent. On a side note I'm not sure if this can be useful but my TI-83 Plus serial number ends with N-0700A.
« Last Edit: October 27, 2010, 11:07:44 pm by DJ Omnimaga »

Offline FloppusMaximus

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Re: On-calculator app signing
« Reply #21 on: October 27, 2010, 11:43:03 pm »
It looks fine to me.  Though, it looks like you probably would run into the apps-getting-deleted issue I was talking about, if you could actually get Axe to compile apps.

But it sounds to me like for whatever reason, the Flash unlocking code isn't working correctly.  The problem is, the way Brandon's method works involves sending some invalid commands to the Flash chip, and different chips may respond differently.  The method used in the program I posted above should be somewhat more robust, although I haven't tested it on all the possible platforms yet.

(By the way, my 83+ BE is even older - 1199A - and Brandon's method seems to work fine.  So, who knows.)

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Re: On-calculator app signing
« Reply #22 on: October 27, 2010, 11:48:20 pm »
Weird. I wonder if it's random from calc to calc...

Where does your calc come from, though? Most people here had their calc made in China, but mine was made in Taiwan. Could they have used different or even failing hardware there?

Offline FloppusMaximus

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Re: On-calculator app signing
« Reply #23 on: October 28, 2010, 12:00:51 am »
It says it's from China.

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Re: On-calculator app signing
« Reply #24 on: October 28, 2010, 12:10:33 am »
Actually disregard what I said... it's my other 83+ (with a broken link port) that is from Taiwan. I got confused because I use the other one so much now so it almost feels like my original 83+. X.x. I guess factories might not make a difference, then. My bro got this one at Staples and I got my broken one at Radio Shack back when Radio Shack still existed over here.

Offline FloppusMaximus

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Re: On-calculator app signing
« Reply #25 on: December 05, 2010, 10:11:33 pm »
Bump!

Here is the first version of my on-calculator app signer.  The name was kind of inevitable, following the grand tradition of silly names for third-party app signing tools.

I've tested this with a number of different configurations, in emulators and on real calculators, but I can't test everything.  So please try it out and let me know if it works (i.e., after signing an application, can you then send it to another calculator?)  You should also, of course, let me know if it crashes and wipes out all your programs.

It should be mentioned that this program currently does not work on "Chameleonized" calculators.

Quigibo, if you're reading this, you should take a look at the example code (example.asm) which is included in the package.  It shows how to set the expiration count and app-installed bit for a newly installed app.  Anyone else who's interested in compiling apps on the calculator may want to have a look at it, too.

(Trying again...)
« Last Edit: December 05, 2010, 10:32:51 pm by FloppusMaximus »

Offline jnesselr

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Re: On-calculator app signing
« Reply #26 on: December 05, 2010, 10:20:34 pm »
Attachment coming soon to a forum near you...

How long does it take to sign it? Does it work on multi page apps?

Offline FloppusMaximus

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Re: On-calculator app signing
« Reply #27 on: December 05, 2010, 10:24:58 pm »
Yes, it should work for multi-page apps.

Computing the MD5 hash takes about 4 seconds per page on an 83+ BE, 1 second per page on an SE or 84+.  After that it takes about 50 seconds on a BE, or 20 seconds on an SE, to compute the signature.

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Re: On-calculator app signing
« Reply #28 on: December 05, 2010, 10:25:59 pm »
That's faster than I thought! I remember Quiguibo said it might take about 10-15 minutes.

Offline FloppusMaximus

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Re: On-calculator app signing
« Reply #29 on: December 05, 2010, 10:30:59 pm »
Yeah, BrandonW wrote a program to re-sign the calculator OS (not apps, but it's a similar amount of work); I don't remember offhand how long that program was supposed to take, but it was somewhere on the order of 10-20 minutes.  Anyway, that program wasn't very optimized. :)