mat h a écrit :
> well put.
>
> Personaly here are my ideas on the matter:
>  - I proposed a JTAG finder circut earlier I dont hhave the technical
> knowlege to build this. Would it work?
>  - Flash reader for the ipod?
>  - If the firmware updates the flash surely there must be a way to
> find the messages going in and out. (Im working on this.)
>   
For a jtag : we first need some basic info on what the device has for 
instruction code, if we can find. instruction code length is absolutely 
needed.
Reading out the firmware ROM on the nano 2 could be a good option (if 
ever connected), because probably more available infos. But hooking to 
the SOC is also possible, but probably much harder without info.

then we need to find the jtag test points (if not removed)
 a method i just saw for this is to examine the pcb after a somewhat 
brutal unsoldering : 
http://www.blackhat.com/presentations/bh-europe-04/bh-eu-04-dehaas/bh-eu-04-dehaas.pdf
 
slide 17
this supposes that the pinout of the SOC is known, including jtag 
connection. If not, we can try to guess, eg 5 testpoints in a raw, but 
this is unlikely

then we need to hook a jtag interface. Quite standard  and compatible 
with most tools is the xilinx paralell cable IV : 
http://www.xilinx.com/support/programr/jtag_cable.pdf (attention to note 
2 !!). I have some readily available.

finally we have to hope there is no fuse or similar system that blocks 
acess to the readout.
also seen on some systems : removing testpoints, or grounding testpoints 
under the IC.

sto


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