Im a few pages deep into Tutorial section, but cant seem to find a tutorial to do this SXOS to Atmosphere transition. Specifically from SXOS emunand to Atmosphere Emunand. And to make SXOS dongle work to boot it.
What's your current SX OS setup?
Do you use it on sysNAND or emuNAND?
If emuNAND -> partition based or file based?
In most cases, "transition" is
no issue at all.
If you're using emuNAND there might be one or two small things you need to do. Apart from that you
just boot into Atmosphère and you're fine.
As for the dongle (you mean the SX Pro on an unpatched unit and
not the modships like SX Core / SX Lite I guess?), that's pretty easy too:
https://gbatemp.net/threads/convert-any-payload-to-tx-boot-dat.518932/
You just need a PC with python + SX OS boot.dat + a payload you want (like hekate).
Place hekate on your SD and rename it to payload.bin or hekate.bin, then edit the python script to point to payload.bin or hekate.bin (doesn't really matter) and run it. Place the altered boot.dat on your SD and use the SX Pro dongle. Done.
If you update hekate, just place the updated hekate payload on your SD and rename it to payload.bin or hekate.bin and that's it.