Retrieving game saves from SX OS EmuNAND files after accidental 6.2.0 update using Wi-Fi OTA

Discussion in 'Switch - Tutorials' started by PsychOsmosis, Nov 29, 2018.

  1. PsychOsmosis

    PsychOsmosis Advanced Member

    Jan 18, 2016
    While playing on SX OS EmuNAND, you accidentally selected "Update" on the update prompt that shows up EVERY SINGLE TIME you go from the homescreen to a game? Now your EmuNAND won't boot anymore?
    Look no further, here's the solution to all your problems!!

    This guide will show you how to retrieve your game saves from the dead EmuNAND files resting on your SD card and how to "downgrade" your EmuNAND back to the firmware version your SysNAND is on!

    Don't forget to regularly backup BOTH your SysNAND and EmuNAND (by copy-pasting it from your SD card to your PC for the latter)!!

    Here's what happened in my case :

    EmuNAND was accidentally updated to 6.2.0 using Big-N's OTA update prompt.
    SysNAND was on firmware 5.1.0.

    EmuNAND would (obviously) not boot at all, while SysNAND was working fine. My fuses were not burnt as I have AutoRCM enabled.
    I hope you had AutoRCM enabled too, as I think your fuses would burn when the console tries to reboot after the update if it was not enabled.
    Although maybe the fuses wouldn't burn as your reboot would be on your SysNAND which is still on a lower firmware, but I think the update gives the command to the bootloader to burn the fuses regardless of the firmware that the Switch is being booted to.

    I did a backup of the Emunand files on my computer by copy-pasting them from the SD card.

    I merged the four parts of full.bin using windows cmd :
    copy /b full.00.bin + full.01.bin + full.02.bin + full.03.bin full.bin
    I then opened the newly created full.bin using hacdiskmount and double-clicked on the USER partition.
    At the bottom of the previous screen, the log showed that the secondary GPT had an offset error.
    I input the two parts of BIS Key 3 (I obtained them using biskeydump v7) and clicked to test them. The verification failed.
    I mounted the USER partition anyway after installing the Virtual Drive driver.

    I then used this tool to retrieve my game saves and unpack them :
    I copied all the folders located in the "save" folder of the newly mounted EmuNAND USER partition to the "save" folder of the tool.
    I double-clicked "run.bat".
    All your saves are now located in the "out" directory.
    I used a previous Checkpoint saves backup to figure out which folder corresponds to which game, and moved them all in their respective game folder (in the Checkpoint folder of my SD card).

    I booted on SysNAND, restored the saves using Checkpoint, and confirmed that they were in working order.

    I booted back on the SX Pro bootloader, deleted EmuNAND entirely and created a new Emunand (on firmware 5.1.0 since that's the firmware my SysNAND is on)!

    Voilà, if you follow the same procedure I did (and have not burned your fuses because you had enabled AutoRCM before the accidental update), you now have a fully working EmuNAND back on a lower firmware and you can now forget about this whole ordeal!!
    Last edited by PsychOsmosis, Dec 8, 2018
    rafaelia, Goro87, Thesolcity and 2 others like this.
  2. Thesolcity

    Thesolcity Wherever the light shines, it casts a shadow.

    Oct 2, 2010
    United States
    San Miguel
    Also keep regular backups of both your SYSNAND and EMUNAND. OP, why did you not mention this? :P
  3. PsychOsmosis

    PsychOsmosis Advanced Member

    Jan 18, 2016
    You're right, I forgot to do so. I added it to the OP.
    Thanks for pointing it out!
  4. rafaelia

    rafaelia Member

    Feb 17, 2010
    This helped me out, thanks :)
    PsychOsmosis likes this.
  5. Bicihere

    Bicihere Newbie

    Dec 10, 2018
    I followed your guide, merged all emunand's bin files, mounted user partition with hackdiskmount using biskey 3 extracted from the switch, but in the save folder there are a lot of file without extention named with a lot of zero and some final number and letter. I tried anyway to copy that in the save folder of the tool you linked but for each file it try to elaborate, it gives an error. You say in the save folder of emunand should be other folders, but i havent them. I missed something? I did something wrong?
    Could you please help me?
    Thanks a lot.
  6. PsychOsmosis

    PsychOsmosis Advanced Member

    Jan 18, 2016
    That's normal behavior, it also gave me an error for each file in the command prompt but then it processed the files anyway and eveything works fine.
    Just make sure you executed it as Administrator in case it matters (it usually does).

    Basically after you processed the files of the save folder (the files with a bunch of zeros in the filenames), you will find your extracted game saves in the "out" folder, but the folder names are also made of a bunch of zeros. You need to use a previous Checkpoint backup to compare and find out which folder corresponds to each game. Then you put them all in their respective game's folder (in the Checkpoint folder of your SD card) and you use Checkpoint to restore the game saves.

    If you don't have a previous Checkpoint backup, you can run all the games on SysNAND to create a new save and use Checkpoint to create a backup so you can compare with what you extracted.