Downgrade Nougat on Nougat with S-ON works: https: //forum.xda-deve...73066566&postcount=435
Yesterday on Oreo did - also works .. the only difference is that in Download mode the software version before RUU firmware does not change (from another place it is taken), with the fastboot command getvar all shows the changes. Tried and the option with the removal of the number of the software and the option with forced inscription of the required .. lay out with the removal, because. it is simpler and less likely to make mistakes (for Nougat and Oreo, for example):