I am going to try this over the weekend, a friend just said they got a low SN used on 6.2.
Buy sxox license
Use tx to make a nand backup
Use this guide to dg to 6.1
https://gbatemp.net/threads/how-to-install-run-any-switch-firmware-unofficially-without-burning-any-fuses.507461/
Boot into RCM...