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