1.1) Download the rom Dynamics v2.2 - WP7.8 RTM
http://WindowsPhone.livedrive.com/item/02650884ad7c4323ab397772db4c4dd4
1.2) unzip, connect usb, run DFT_WPI_SAM1.exe
1.3) Trun off the phone, hold sound- , camera, and power, run DFT_WPI_SAM1.exe again.
1.4) until finishing flashing, unplug usb.
1.5)waiting for 10 min. Done!
2) Unlock
Buy a unlock code through internet (around 4 dollars!)