(1) You wrote "logged in" so you missed the part about clearing passcodes and special offers.
(2) You missed the part to use the 5.7.4 firmware version, because 5.6.1.1 bootloops all too often.
Now you have a bootloop because of (2) and it will not export USB storage until you log in because of (1), which is a bit hard to do while it is bootlooping.
Welcome to the world of serial port debricking.