I am in the same situation with 2 PCB's.
Both can be flashed ok, but functional they are a mess.
One of them eject the dvd tray, the console is stuck 30 sec to 1 min to Xbox 360 logo an you either get E64 or Open tray.
The other one, it dosen't even eject dvd-tray.
Also there are 2 lots or factories where the PCB are comming from.
The smooth functional without problems is the one with the white switch for unlocking Spi and green QC Passed sticker.
http://www.youtube.com/watch?v=FmX7eSKuzkw
The one with the problems has the switch black and the QC Passed sticker is golden.
http://www.youtube.com/watch?v=3bBdPo3yQrk&feature=related
Please confirm witch switch and sticker do you have on faulty PCB's.
Hope to resolve it by warranty.
And if this may count, i appreciate the effort from TX to make a total solderless solution, but we could get rid of the mechanical contacts, and spare 1-2$
Soldering 5 wires is not a hard job for anyone who is modding a console.