Rockbox Development > New Ports

Cowon D2

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it seems as if someone has managed to get hold of recovery drivers. Users are reporting of a successful recovery on a faulty D2. This is pretty gd news.

Page 9 and on wards:

I can provide the recovery driver if anyone is willing to port Rockbox to Cowon


--- Quote from: man.dovvn on May 31, 2007, 09:11:35 AM ---I'm a 3rd year eng. student with some experience in digital processors, hardware & coding. I also have a colleague who is 3rd year electrical eng, so that oughta help too.
I have a feeling it's gonna be a lot of work...

--- End quote ---

After posting I did a bit of research - going through the datasheets of various ICs and all that. One thing I am not sure is how different the Telecips TCC7801 is from the ARM926EJ-S reference manual. I couldn't find the datasheet for TCC7801  :(.

I think there are two plans of action we can take - please feel to add or suggest better ways -
1. Try to understand the structure of the firmware binary - organisation and disassembly.
2. Try to trace the schematics and connections of the circuit board.

I found a few forum posts via google on some south east asian (thai I think) forums which had the disassembly pictures. Also the iRiver Clix uses the TCC7801 (again through SE Asian forums).

What's your take on the issue?

anythingbutipod has a disassembly set of pics. We'll have to take a look at any progress made on the clix that we can transfer over, I'm not expecting much though. If we have recovery drivers, we can write test programs for the D2 according to the ARM926EJ-S manual and see what works. If we trace the schematics we can use a program to simulate the hardware, making testing & design a much easier and faster process. & I haven't any experience in decompiling/reverse engineering firmware. I am pretty good with coding though, & I have had some experience with ICUs & the coding limitations of hardware.

Even if we can trace the schematics we still have no way of knowing the internal topology of the 7801. If I understand correctly it contains two processors - ARM926EJ-S and ARM946E-S and many peripheral controllers - LCD, Touch scree, SD card, USB etc.

To understand all these we'll have to reverse engineer the firmware. And possibly probe the pins when we can get a program running on the processor.

I also don't have much experience with reverse enginneering so am struggling a bit. Current plan is to get the recovery drivers and snoop at the USB traffic to see what commands are being sent. Am also trying to get hold of an ARM simulator which we can simulate the firmware in. Do you know of one?

Did you try anything since your last post?


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