Although SandForce's SF-2281 controller has been shipping for well over a year at this point, it took Intel to discover a bug in the controller that prevents it from properly supporting AES-256 encryption. The bug is at the controller level and can't be fixed with a firmware update. AES-128 encryption works perfectly fine as does the drive's standard, un-encrypted operation mode. If you have an Intel SSD 520 and need AES-256 support, Intel has introduced a return program. If you purchased your 520 on or before July 1, 2012 you can contact Intel for a full refund of purchase price. You have to complete the request by October 1, 2012. If you want a Cherryville/SF-2281 drive with proper AES-256 support you'll have to wait a few months for a new spin of the controller it seems.