LG G4 H810 stuck in boot loop, can this be fixed with Octopus box or Z3X


I have both boxes! I am just starting out with phones and have done a few successfully! But I have an opportunity to pick up an almost mint condition LG G4 AT&T H810 version for $ 125 .. it was already unlocked and clean imei… but he says it was rooted and now stuck in a boot loop

how hard would this be to repair?? I know of the LG G4’s the h810 seems to be the "easiest" and most favorable one to work on

let me know if its possible and how…would it involve just reflashing the firmware?