Same issue with MBP Early 2015. @sf98723 Thanks a lot for your instruction. I have tried your steps, but after the last step (csrutil enable) , I also had the restart loop problem as  McQueen_69 and mergenc. @mergenc Thanks for your input, I tried to run 'csrutil disable' in rescue mode again, the restart loop problem fixed. Seems MBP 2015 has a little different with MBP 2014 😂