Author Topic: OS 3.0.2 downgrade now possible with DowngradeFix  (Read 11777 times)

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Offline Lionel Debroux

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Re: OS 3.0.2 downgrade now possible with DowngradeFix
« Reply #30 on: July 24, 2011, 10:24:31 am »
Yes, it was somewhat tested on emulator before being thrown to a real Nspire.
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Offline Munchor

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Re: OS 3.0.2 downgrade now possible with DowngradeFix
« Reply #31 on: July 24, 2011, 10:25:38 am »
Yes, it was somewhat tested on emulator before being thrown to a real Nspire.

Is there a screenshot? My Nspire is 50KM away :S

Offline Lionel Debroux

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Re: OS 3.0.2 downgrade now possible with DowngradeFix
« Reply #32 on: July 24, 2011, 10:30:05 am »
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Offline Munchor

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Re: OS 3.0.2 downgrade now possible with DowngradeFix
« Reply #33 on: July 24, 2011, 10:32:46 am »


But that's being launched from OS 1.7. A true OS should be launched on boot, I think.

Offline JosJuice

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Re: OS 3.0.2 downgrade now possible with DowngradeFix
« Reply #34 on: July 24, 2011, 10:36:42 am »


But that's being launched from OS 1.7. A true OS should be launched on boot, I think.
We need the RSA keys to do that.

Offline Munchor

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Re: OS 3.0.2 downgrade now possible with DowngradeFix
« Reply #35 on: July 24, 2011, 10:37:10 am »


But that's being launched from OS 1.7. A true OS should be launched on boot, I think.
We need the RSA keys to do that.

Which was my point :)

Offline Lionel Debroux

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Re: OS 3.0.2 downgrade now possible with DowngradeFix
« Reply #36 on: July 24, 2011, 10:38:11 am »
Agreed, and notice that I used a pair of quotes in one of my above posts ;)
But for now, this kind of things doesn't exist, for obvious reasons: we don't have TI's private key (and basically can't obtain it through indirect means, as you know), so we cannot produce an OS that the Nspire would accept ;)

Making our own OS is a fully legal purpose. But TI doesn't want to let us do that. And even if we were able to trick the Nspire into accepting the installation of an unsigned OS, we'd also have to trick the boot2 into launching the unsigned OS, which adds a level of difficulty.
I did not write that it's possible or impossible - I don't know. But it's hard, and highly dependent on the boot2 version, too.
« Last Edit: July 24, 2011, 10:42:02 am by Lionel Debroux »
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Offline Sebasu

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Re: OS 3.0.2 downgrade now possible with DowngradeFix
« Reply #37 on: August 16, 2011, 06:12:40 pm »
To downgrade OS 3.0.1 we need special hardware if TNOC didn't be used
has somebody tested sending a TI-Nspire.img file by the RS232 comunication to have a CAS OS installed on a nonCAS handheld?
or it is imposible?

Offline critor

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Re: OS 3.0.2 downgrade now possible with DowngradeFix
« Reply #38 on: August 17, 2011, 04:58:41 am »
On non-CX calculators, you can send a TNC/TNO file through RS232, but it is checked the same way.
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