Root Permission Problems On 6.2.4

Oct 2, 2015
Hi all,
after big software problems due to a damage to file system (solved),i returned on Roms,starting from 5.12.10.i istantly upgraded it to 5.12.17,then updated to 6.2.4 after partitions fusion.I did a factory reset only when i flashed the first one,then i did just cache/dalvik wipes.The phone has not problems,is perfect,except 1 thing: i can't obtain root permissions from security --> permissions,and it is confirmed by root checker and SuperSu. Also,the update replaced my TWRP recovery (2.7 version) with MIrecovery. What can i do to obtain again those permissions?
thank you very much