In a
previous news, we were focusing on the TI-Nspire CX/CM startup screens.
Unlike monochrome TI-Nspire, these calculators include a graphical data stream in the first pages of their NAND memory chip, a part called the Manuf zone. That stream is used during startup by both Boot1 and Boot2.
So far, we could dump up to three different samples of this data stream:
- on production TI-Nspire CX/CM
- on TI-Nspire CM EVT prototypes
- on TI-Nspire CX EVT prototypes
It turns out that the content format has remained exactly the same.
This graphical data flow in RGB-565 has remained a mystery for a long time because it is not visible in NAND dumps. Indeed, it is compressed - but we're not surprised to discover that it's the same compression format as the Boot2, which avoids the small Boot1 to have to manage various decompression algorithms.
This flow is also signed with the same RSA keys as the Boot2, Diagnostics software or OS. That means that it's going to be rejected in case of modifications, and the calculator in this case boots with a default screen similar to the one on monochrome TI-Nspire.
And yet, today is a great day. I'm releasing a tool which will probably be my penultimate Ndless 3.1 program, mySpire, a splash screen editor for the TI-Nspire CX/CM!
How is this possible ?
The startup screen does actually include a maximum of 12 displayable elements which are extracted from the signed data stream. On the data streams we could dump, only 8 of these elements are being used.
And all the parameters about these elements
(position, size, part of the data stream...) are unsigned and therefore freely editable!
We can therefore move all of these elements, and even reuse a part of an element in another one!
In fact, the logic is completely different from the one of an image editor, because here you're controling the container instead of the content.
But after an adaptation phase you will realize, however, that we can still do very cool effects.
By expanding an element horizontally, one can for example tilt it to the right or reduce it and even make it appear several times!
By compressing element instead, you can tilt it to the left or enlarge it!
There's even an option to shift the RGB-565 and get new colors!
And as Texas Instruments kindly left us 4 free items, by borrowing to uniform areas of the data stream areas we can build fun shapes for example!
Note that mySpire is a simple file editor. The changes will be applied to the calculator once you flash the modified Manuf image to the NAND memory using another tool like nsNandMgr.
You are therefore free to take all the time necessary to train yourself, to get use to the logic of the RGB-565 date stream containers modifications, and to create your customized boot screen in several times!
With mySpire and nsNandMgr, your TI-Nspire CX/CM becomes finally yours and you can customize it according to your desires!
It is also an excellent way to mark your calculator against theft, since there is no official way to cancel the changes.
The only way to rollback is to flash a backup of the original Manuf image using nsNandMgr again.
Look at this... Isn't it beautiful?
And for those who think to a simple trick with mViewer displaying image, I 'm going to show you the creation and flashing of another custom boot screen:
(jump to 8'45 to see directly the reboot with the custom splash screen)Downloads:mySpirensNandMgrSource:http://tiplanet.org/forum/viewtopic.php?f=43&t=13071&lang=en
