It appears that unlocking your bootloader through HTC Dev can cause a few problems on a few devices. Nothing serious, mind you, but enough for contributors around XDA to put up tutorials and fixes to help people get it fixed. It is also very unclear to a number of users as to what unlocking via HTCDev actually does. Fortunately, for those carrying the HTC Sensation, your questions and fixes are all in one place. XDA Senior Member trkaaa has written up a very nice thread that not only explains exactly what HTC Dev is designed to do, but identifies the most common problems with unlocking the bootloader this way and has listed ways to fix those issues.
The explanation and fixes are very thorough and very friendly to those who may not be as tech savvy as they’d like to be. It mentions the difference between unlocking with tools such as Revolutionary and unlocking with HTC Dev, and why users see S-ON even after unlocking. The big fix that’s listed, which is causes WiFi issues, has been linked to flashing ROMs and not being able to flash a kernel in recovery. This then causes a mismatch between the kernel modules and the kernel itself, leading to the issue. As explained in the thread:
the kernel is located inside Boot.img , and Also the kernel components ( when you install a rom ) are located in System \ lib \ modules . the Module Folder is a Kernel Folder . if there is a mismatch between kernel and kernel components you will have WiFi error
There is a lot more information packed inside this helpful thread, so any and all new HTC Sensation users—as well as some more experienced ones—could learn quite a bit by taking a look at it.
More information can be found in the original thread._________