1. You root the ROM, not the hardware, so rooting, then flashing a new ROM is wasting the time it took to root. If the new ROM isn';t rooted, you'll have to root again.
2. Unless the ROM you flashed was an S9 ROM modified to run on an S8, it won't.
As for rooting again, the "unlock after 7 days" thing is to SIM-unlock the phone - to be able use another carier's SIM in the phone - it has nothing to do with rooting. You can root any ROM you have a rooting method for, at any time.
04-05-2018 01:56 PM