iAUDIO U3 (formerly New hardware--scans...)

[Llorean]

http://www.rockbox.org/twiki/bin/view/Main/NewPort
Feel free to start an effort.

[vitja]

Hi, all!

I found something about original firmware package. it contains: data[1-3].dat and executable, that
actually copies files to player.

data1.dat - is new firmware, it should be copied to the players root as U3_fw.bin
data2.dat - is font upgrade, U3_font.bin
data3.dat - is 1.12 firmware

Now firmwares 1.13, 1.21 could be downloaded from cown site, so we have 3 different firmwares to play with.
I was trying to modify firmware, but I didn't find what kind of checksum is used there.

tcc770 is based on arm946e-s, here is datasheet: http://rtds.cs.tamu.edu/web_462/techdocs/ARM/cores/DVI0022A_946E_S(R1)_po.pdf

One question: is there o-s arm binary disassebmler? I've written the one based on binutils, i guess that is should be already written.

[nilux]

Hi there, it's my first post here

I'd be *really* interested in an iAudio U3 rockbox port and would like to help make it possible, so if there is anything (not to complicated : i can open my unit, but i'm not that good at electronics; i have no problems typing commands in a terminal but i can't code) i could do, just tell!

You talked about disassembling the firmware, what does it exactly mean?

[markun]

http://en.wikipedia.org/wiki/Disassembler

[cerr]

I downloaded version 1.21 from http://www.cowonamerica.com/download/iaudio_u3_jsfw.html (even tho my player's been loaded with 1.26 by default) and tried to disassemble it using dasm2 (http://www.lxtreme.nl/index.pl/source/alive/dasm2#download) but all i'm getting is "../cowon/U3_FW_1.21/data1.dat: File format not recognized". Has anyone had any success decompiling it? If anyone came up with a disassembled piece, I would run it thru a decompiler and go from there. I would be ready to contribute some coding...

[saratoga]

I downloaded version 1.21 from http://www.cowonamerica.com/download/iaudio_u3_jsfw.html (even tho my player's been loaded with 1.26 by default) and tried to disassemble it using dasm2 (http://www.lxtreme.nl/index.pl/source/alive/dasm2#download) but all i'm getting is "../cowon/U3_FW_1.21/data1.dat: File format not recognized".

Thats not going to work.  Instead, you should use the objdump included in the rockbox dev tools or another ARM disassembler. 

Has anyone had any success decompiling it? If anyone came up with a disassembled piece, I would run it thru a decompiler and go from there. I would be ready to contribute some coding...

Decompilers don't really exist in the sense you're probably thinking.  Generally the best the computer can do is disassemble the binary to show you the actual assembly instructions (in this case they would be ARM).  Then you read those to try and figure out what they do, or at least figure out enough to work on a port.