People close to Team Xecuter, Team Xodus aswell as 'independents' have worked together and tried alot of different possibilities and came to the conclusion that the MCPX-code didn't change. (exploits like the RC4-check bypass (used in multi-version bioses) have not been removed by Microsoft, they also didn't use a better hashing algorithm). This means no new bios must be made (a multi-version bios will work fine).

Ubergeek (Team Xecuter) succesfully booted his v1.3 xbox with a X2 4976.02 bios flashed on his TSOP. (he replaced the original 256k Winbond TSOP with Amic 29F040 512k ('cause he had problem to write on the winbond chip) ... that's also a nice hack ;))

The problem on the new xbox version are the LPC points. "D0" is still there and doing it's work but Team Xodus pointed that Microsoft changed something with 1 of the LPC points: LFRAME (pin#3) is 'gone' (it's not connecting with the MCPX anymore).

Homebrew 29-wire (or optimized gen2 12-wire) modchips have not been tried yet, but it's expected these will still work. (flashed with a multi-version bios)

Now that they know the exact problem - they can try to work on a solution. We'll report more as soon as there's something important :-)

Also note:
There is still no decent way to see the difference between a v1.2 and v1.3 ... we will try to find a visual difference as soon as we manage to find a v1.3.