@Kabouik, Looking at your steps it goes wrong on step 5 when I connect it to USB. I'm on windows by the way. I already flashed Sailfish on it several weeks ago and went back to Android to try out the flashing proces.

Does your bootloader menu show any versions?
Because mine doesn't. It does show the rest. Product_name (msm8998), variant (MSM UFS), serial number, secure boot (no) and device state (unlocked).

Did I mention that the LED is red when connected to USB?