Question Just switch to emuMMC, question regarding emuMMC backup and FW update

Discussion in 'Switch - Exploits, Custom Firmwares & Soft Mods' started by barbilio, Jul 19, 2019.

  1. barbilio
    OP

    barbilio Newbie

    Newcomer
    1
    Jul 9, 2019
    Netherlands
    Hi all,

    I have just successfully migrated from CFW on sysNAND to CFW on emuMMC SD partition.
    My current situation is:
    - sysNAND: System version 7.0.1, autoRCM enabled, CFW AMS 0.9.1
    -emuMMC: System version 7.0.1, autoRCM enabled, CFW AMS 0.9.1
    (They are basically mirrored).

    Some time ago (before emuMMC was available) I updated my sysNAND using ChoidujoiurNX and enabled autoRCM, so no burnt fuses above FW v 3.0.1.
    In the future I would like to restore my original clean NAND backup (OFW 3.0.1) to eventually use warm boot/cold boot options, but for the time being (as I do not use online) I am planning to keep my sysNAND as described above.
    However, I would also like to update my current emuMMC FW version to version 8.0 or above for game compatibility.
    Hereby my questions:
    - I know that I have to use ChoidujourNX to FW update while in emuMMC. But what should I do with the autoRCM option? Should I enable it or not? If not, will my fuses get burnt if I boot from sysNAND CFW? I want to be able to downgrade in the future!
    - how to backup emuMMC in order to restore if something goes wrong in the update process? As far as I got I cannot use nand backup to backup emuMMC.
    - how to restore an emuMMC backup eventually?

    Thank you
     
  2. KrytpicLuck

    KrytpicLuck Member

    Newcomer
    1
    Sep 22, 2017
    United States
    I was on the same boat as you. But took the leap and updated the emuMMMC with ChoidujoiurNX hoping it would do both.
    Somewhere along with all the research I did, it says to disable the autoRCM in ChoidujoiurNX. Someone out there didn't do it and is in a non boot mode after the Switch logo appears on the screen. But disabling autoRCM will burn fuses but hekate has the ability to enable GC to prevent that. Or at least I know it does.
    I finished it and only updated the firmware inside CFW emuMMC 8.1.0 and the sysnand is still at 8.0.1
    Trying to figure out how to update the sysnand now.
     
  3. laz305

    laz305 GBAtemp Regular

    Member
    3
    Jul 31, 2008
    United States
    How are we able to know how many fuses we’ve burnt?
     
  4. KrytpicLuck

    KrytpicLuck Member

    Newcomer
    1
    Sep 22, 2017
    United States
    There’s this program that u will have to inject with TegraRCM called bricmii. That will display the burned fuses. Check your PM
     
  5. ROYGES

    ROYGES Advanced Member

    Newcomer
    2
    Mar 16, 2017
    United States
    Hekate can show you the burnt fuses
     
  6. barbilio
    OP

    barbilio Newbie

    Newcomer
    1
    Jul 9, 2019
    Netherlands
    Thanks for the reply.
    As far as I know, autoRMC will normally change a byte in the NAND/MMC so that your switch is “bricked” on purpose, and then it won’t go through boot phase (so fuse check, fuse burn, etc...). Using choiNX will also overwrite the current RCM option.
    The doubt is: as I want to launch it on emiMMC, will autoRCM be applied to the “fake/emu” NAND/MMC or still to the real one?
     
  7. LeMageFro

    LeMageFro GBAtemp Regular

    Member
    4
    Mar 29, 2018
    France
    You seem to be a bit confused as to how emuMMC works. There is no way your sysNAND could be updated if you use ChoiNX after booting your emuMMC, since everything that should affect your sysNand is now redirected to the emuMMC partition of your SD. If you want to update your sysNAND without burning fuses you have to boot it under CFW and then use ChoiNX. Also the "disable GC" option in hekate has nothing to do with autoRCM so I don't understand why you mentioned it ?

    About barbilio's question concerning enabling auto-RCM when you update your emuMMC, it really shouldn't matter since nothing will be modified in your sysnand. Just to be extra safe I would let autoRCM on personally (in case I made a mistake and were not really under emuMMC when I update for exemple). When you created your emuMMC it copied your sysNAND with autoRCM enabled and yet your emuMMC works fine, so I don't see how having it enabled could be a problem. Just remember to update to the latest atmosphere to be sure it's compatible with the updated firmware.
    And even if your emuMMC really couldn't boot after updating it with autoRCM enabled you could just recreate it from your sysNAND anyway, and then update it without autoRCM enabled.
     
    Last edited by LeMageFro, Jul 22, 2019
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