Originally Posted by mcm_xyz 
Let's make some light!
If you install the full rom you can find here :
http://forum.xda-developers.com/showthread.php?t=922430
named p3_jordan_umts_jordan-user-2.2.1-3.4.2-107_JDN-4-000000-release-keys-signed-T-Mobile-US.sbf
You wont be able to downgrade!
RSD Lite will still work but it will only allow you to install this rom and not an earlier version like 2.34. Most probably will allow you to install future newer roms.
In order to be able to install anything you want at any time you want use boot only sbf or the full roms 2.21 or 2.34 or CN_2.2. Also take care that 2.51 is also locked (can not go down to 2.21 or 2.34 anymore)
