Two years ago, we found some traces of some traces of a SD memory card support in the TI-Nspire Diagnostics software:
That mysterious SD card was needed for NAND reflashing.
But no such reader was present in the TI-Nspire.
Fortunately, we then found a photo of a TI Nspire development board:
And an SD card reader is present in the bottom left-hand part of the image.
As development board are designed to test development builds of the TI-Nspire Boot2 and OS which might be buggy, the SD card accessed from the Diagnostics software can help TI developpers reprogramming the NAND of a development board which won't boot anymore.
So TI might have developped some way of plugging an external SD card reader to TI-Nspire handhelds, either through the dock connector
(J01) either through the internal J04 connector
(unsoldered on production models, but present on prototypes).
We've got no evidence of the existence of such an external reader up to now, and SD card might only be used on TI-Nspire development boards.
But we've just found out something interesting
For back to school 2012, TI has released a new access point for the TI-Nspire.
And just check what's inside, in the bottom left-hand corner this time:
Yes, an unsoldered rectangular place
(J4) for an MMC card reader!
As there are no keys to launch the diagnostics software on the TI-Navigator access points and as they are usually running Linux and U-Boot, using the MMC card might be a little different.
I suppose that U-Boot tries to boot from the MMC card if present, before trying to boot from the NAND.
Source:http://tiplanet.org/forum/viewtopic.php?t=10235