Rockbox Development > New Ports
SanDisk Sansa m200 series (v1)
fiveofoh:
Hmm, I guess I forgot to post here...I put up a wiki page for it with scans:
http://www.rockbox.org/twiki/bin/view/Main/WebHome?topic=SansaM200Port
And whatever info I've gathered. Kr4t05, we may be able to use yours, but I've gotten mine apart to take scans and such, so if I don't have to do anything crazy like ripping the screen off I'll probably be fine. But thanks, I'll let you know :)
alsaf:
I would be grateful if they following questions can be answered.
1) In the fdisk -l summary of M240, there is a difference of about 17Mb between the Disk and Units. Would I be correct in assuming this is a hidden partition where the firmware/bootloader is stored and therefore the M240 will be easy to upgrade?
2) Dan_a mentioned using arm-elf-objdump for debugging. Would I be correct in assuming that ARM (arm-elf) will be used for this player as it is telechips based?
3) I've got Usbsnoopy installed on windows and managed to install a sniffer on another player. I haven't tried it on my M240 yet. Would I be correct in saying that it would have to get a log dump when I am trying to upgrade the firmware? Can this only be done once when the firmware is being upgraded or can I do it afterwards when the Installer is checking firmware upgrade?
4) I found a link to rom files (http://files.zefie.com/PMP/sansa/m200/firmware/), I'm sure I got link from here. I assume this is the firmware rom file that needs disassembled?
Apologies if I am totally on the wrong track here but I have no experience of reverse engineering USB devices. I would say my experience using the C language is intermediate and currently swotting up on ASM (I've got a tutorial on 80386 which will give me an idea of the language, hopefully the ARM version isn't too different?).
Bagder:
1: It depends a lot on how that partition is hidden and how you acccess it etc.
2: Yes, as the CPU core in the telchips is ARM
3: Yes, but the common telechips firmware format is already "cracked". Isn't this working for the m200 series? Also, you should be able to work with this target using tcctool which thus allows you to run and test stuff on target entirely without flashing or risking to brick it etc.
4: Yes
alsaf:
Thanks for getting back to me so quickly Badger.
From my understanding of point 3, I can plug my m240 to my laptop and 'run code' right now. This will help me get my head round the embedded programming part. I've noticed there are a few current porting efforts that use the telechips so I'll look at them to get more info.
Unfortunately I need to 'walk before I can run' so please don't expect too much from myself. If I can keep the motivation up I'll get there eventually.
Bagder:
Just allow me to point out that there seems to exist two different m200 models as well, and if you're having the newer one, it seems it isn't Telechips anymore but AMS:
http://daniel.haxx.se/blog/2007/11/25/has-sandisk-gone-ams/
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