HTC has revealed via their Facebook that they are one step closer to unlocking the bootloaders of the Sensation 4G (T-Mobile) and EVO 3D (Sprint). They are currently testing the system and hope for a September release.

From HTC Facebook:

We’re thrilled to announce today that software updates to support bootloader unlocking will begin rolling out in August for the global HTC Sensation, followed by the HTC Sensation 4G on T-Mobile USA and the HTCEVO 3D on Sprint. We’re in the testing phase for the unlocking capability now, and we expect it to be fully operational by early September for devices that have received the software updates. We’ll continue rolling out the unlocking capability over time to other devices as part of maintenance releases and new shipments.