The method involves a lot of steps and temp-bricking your EVO 4G LTE, placing it in Qualcomm Download Mode. The full steps are outlined in the link below and could end up bricking your phone if done incorrectly (or even perhaps correctly).
I’d advise that people hold off attempting this method until a developer has managed to get a foolproof automated method in place, or at least until someone’s written up a step by step guide for the casual root user.
It’s a great day for those who are at HBOOT 1.15, as S-OFF is now within reach. Hopefully the same will be found to work for HBOOT 1.19 and we’ll have no restrictions on this phone whatsoever. It continues to be an exciting development run we’re seeing for the latest EVO.
[xda-developers] Thanks, Migueal!