TI-H: FLash modification of a TI89
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TI-H: FLash modification of a TI89
Shure, it is teoretically possible, but not practically viable.
checksums are made that way, that the smallest change of data chnges the value
of the checksum a lot, in a chaotic manner.
In a HW1 calc though, you CAN change the rom, through some mistakes in Ti:s code
in the bootloader. (It's more a mistake then an actual bug). This is very tricky
and it is as far as I know fully possible to render your calc useless for ever.
(Or.. until you desolder the flash chip, put it in a stand alone flash
programmer, programs it, and solder it back..)
The bootloader checks some bytes in page 1 of the ROM (starting to count from 0,
with the bootloader in page 0), and if theese bytes are not as they should, the
bootloader halts, without giving you any oppertunity to flash your calc.
Archive Utilities uses this thing.
In HW2, they fixed this as far as I know..
//Olle
"M. Adam Davis" wrote:
>
> Knowing that the checksum is of a specific length, it is /possible/ to change
> enough of the rom in specific ways to keep the same checksum...
>
> But it would also be quite a bit of work.
>
> -Adam
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