My understanding is that this and similar techniques don't get you back into the before first unlock (BFU) state. To do that as far as I know you have to shut down the device. Otherwise--even if locked--your phone will be in the after first unlock (AFU) state. I believe that in the AFU state considerably more of the system is decrypted and accessible than in the much more limited BFU state.
Maybe someone with more knowledge can chime in here.
Maybe someone with more knowledge can chime in here.