Source: Xbox-scene.com
Here’s an overview of some of the progress made by the Free60 Project over the last few days. For those who missed earlier news the project aims to port open source operating systems like GNU/Linux to the Xbox360.
* Some info about the stock HD: It’s a Samsung or Seagate drive, it’s not locked, drives file format is unknown (possibly FATX or NTFS derivate), so far no reason to believe content on HD is encrypted. There’s also a full pin-out of the SATA connector and some more info about the drive content. Check it out here.
* Boot initialization details of the PowerPC 64-bit 970FX CPU. This is not the Xbox360 CPU, but it’s probably similar. There are also some technical details/guesses about the architecture of the 360 CPU, you can check it out here.
* The Xbox360 can read iPod and standard USB flashdrives using HFS+, FAT(32)(?) filesystem. More about USB here.
* Lot’s of info about the chips used on the Wifi Adapter PCB is available here.
* The (US) Xbox 360 ships with kernel and dashboard 2.0.1888.0, upon the first live update the dashboard and kernel are updated to (D:2.0.2241.0 – K:2.0.2241.0) BK:2.0.1888.0. It’s speculated that a backup of 2.0.1888.0 remains in the backup kernel storage. More here.
* Some info about UPnP (Universal Plug and Play): it runs on TCP port 1026 and seems to adhere to UPnP MediaRenderer Specifications. The 360 also uses UPnP to talk to Windows Media Connect and routers. Read more here.
* XEX File Format Speculation/Info: “XEX is the executable file format used by the Xbox 360 operating system. It seems to be a crypto and packing container for PPC PE executable files, comparable to UPX or TEEE Burneye. This would give more creedence to reports of .xex’s being gigs large. Such speculation is also fueled by the presence of what appear to be clear text file and folder names. If games are Gigabyte sized .xex files then it’s likely the 360 knows how to grab the section it needs into memory and decrypt/decompress on demand, instead of traditional all at once extraction. The executable code seems to be crypted, though, there exists some uncrypted XEX files in the wild.
A XEX file is composed of the following:
-A 32 bytes XEX Header
-Variable-length program/section headers
-Program/Section content “
More including info about Cryptography and Structure of the XEX File here and specifically about the Backwards Compatibility XEX update here.
Also more technical info about the XEX file format on this XBH thread. They found a SHA1 sums in default.xex (BC update file). More at source(xboxhacker.net)