if your switch is an un-patched one, that depends on the method you use to inject the payload, most of us use a external gadget like the RCM Loader which can be updated connecting to a PC and copying the new payload to the USB Drive. other uses a phone so you need to update the file on the phone, other uses Windows tegraRCM tool so you need to update the file on the folder, etc.
if your switch is patched and have an internal Chip, then you only need to update the file PAYLOAD.BIN on the root of your SD card.
updating Hekate is as easy as copy the new files on the SD card and before anything you boot on NYX (pressing VOL- while injecting payload) then on NYX you can make the SYSNAND Backup
the first EmuNAND you create es a exactly copy of your actual SYSNAND so you don't loose any game.
Yes, if you don't enable "No Gamecart (NoGC)" on atmosphere nor Hekate.
AutoRCM is a config where a bit is changed on you NAND so from that moment the Switch never boot on OFW (official firmware) instead the switch always boot to RCM mode, what is the same mode you switch boot if you put a jig on right rail and press VOL+ while you power the switch. so you gain two things:
- you don't need put the jig and press VOL+ to load your CFW anymore.
- your SYSNAND with OFW never load again and you don't risk to burn fuses (a little thing inside your switch which nintnedo put for avoid a Firmware downgrade).
but in other hand you switch always power on to a completely black screen until you inject the payload.
NEVER ACTIVATE AUTORCM on a Patched system most of the internal chips are incompatible with AutoRCM.
