So i was messing with this last night with my Mariko switch,
Ill try and make this as clear as i can.
from what i noticed reading though this and some other documents i found online , as well swapping to Atmosphere.
There is only one way to dual boot that i found witch will require alot of memory,
make a emunade in sxos (or have one) , leave untouched,
instead of swapping out the boot dat file for inorder to boot directly into hekate for atmosphere (included in Sx_Gear_v1.1).
leave the boot.dat alone. (sxos_3.1.0_beta Boot Dat)
Youll have to navigate though the menu to find payloads and then you can boot into hekate ,
make a system nand backup in Hekate even if you already made on in SXos and keep it on your pc
From there normally you would Migrate emuMMC from sxos,
instead youll have to make a new emunade of your internal system.
That should allow you to boot into Atmosphere via Launch
Now if you updated your sxos Emunand though ChoiDujourNX like i did (not the internal system)
and want to migrate your sxos emunand to atmosphere , youll have to do something to get it to work right
the system backup you did in Hekate grab the boot0/boot1 and replace the boot0/boot1 in your emunand
simply replace the files in your sxos/emunand/ folder (if you're using a file based emuNAND)
ChoiDuJourNX corrupts your boot0/boot1 and will prevent you from being able to boot into emuNAND on Atmosphere.
Hekate also has this function for EmuNAND. If you use that, please be sure you're NOT flashing SysNAND
from there you should be good to dual boot both systems, with additional steps.
Basically Sxos will behave normal and anytime you want to boot into Atmosphere,
youll need to Boot to the sxos Recovery menu , Navigate though the menu to payload ,
Boot up
Hekate ,then that should allow you to boot the atmosphere emunand from the launch menu.
the Pkg1 decryption failed! error , i managed to fix this by going to hekate then tools ,
click the second touch option and dump Package 1/2.
If you get a failed to match warmboot with fuses - sleep mode wont work .
Thats because the emunad you made is not updated to the latest firmware
This is a system check to see if fuse match the up to date.
Youll have to use daybreak to Updated your emunand
https://github.com/CTCaer/hekate/issues/616
There might be a easier way to dual boot then the way i just described , but this worked for me and can revert back if i wanted to.
Haven't run into any problems atm and tinfoil/hombrew still works n all
my internal system firmware is still 10.2.0 , i have not updated it cause im sure if it would not boot sxos anymore even though it has a mod chip i dont think it would due to sxos boot.dat not being updated
one last thing that im trying to find out but im sure it would, i just want to find more proof ,
if i did update the system internal to 12.1.0 , it would still boot to Hekate , the sxgear package is a bypass to boot to another .bin file (Hekate)