Sysnand firmware downgrade godmode9

[DChronos]

I have a quick question I can't find a clear answer to for cfw users, but I assume is true. I already have Luma 11.0 and b9s 1.4, have had cfw installed for years.

I have an o3DS and just did a sysnand backup on godmode 9 while still on firmware 11.16 (also backed up sd card). I'm about to update to 11.17. If I ever, for any reason, wanted to downgrade my o3DS sysnand firmware back to 11.16, or any other version from backups I made in godmode9, do I just follow the gm9 usage guide to restore this sysnand backup (or any previous version backup)? Would that downgrade my sysnand firmware to the previous version and work just fine?

I realize writing to sysnand can be dangerous, I'm just curious in case I ever wanted or needed to downgrade my sysnand fw, even if I don't plan on it.

Second quick question, what is the essential.exefs file for? Only asking because I don't know if it's necessary for restoring a sysnand backup, I have a few old backups that I don't see this file for. I do have this file in a few places, though, are they all the same?

 

[Hayato213]

Why downgrade?

 

[DChronos]

Why do I have to supply a reason to get an answer? Read the 3rd part. Please don't reply just to ask why.

 

[Kwyjor]

This much is certain: if you try to mess with things people don't usually mess with, then you're likely to encounter problems that no one is familiar with and that no one's likely going to be able to help you with.

It so happens that on rare occasions it is sometimes advisable to use https://3ds.hacks.guide/ctrtransfer , which will downgrade a system to 11.15. Note that doing a standard System Update is part of the process and that it does not actually require the use of personal NAND backups.

 

[KleinesSinchen]

NAND restore (save) from your own backup files works for downgrading.

Be warned there might be big problems with downgrades to very early versions. (Designs not implemented with Home Menu extdata containing newer things, certain games not starting for example).

Given the backup files are good (not damaged/corrupted) this is less risky than playing with homebrew Sysupdater to downgrade or applying CTRTransfer images with low versions (even more considering these methods offer downgrade below versions that can deal with newer devices).

First thing to do before such experiments is full backup of your current NAND and your SD contents.

Good luck and have fun!

 

[DChronos]

NAND restore (save) from your own backup files works for downgrading.

[snip]

Ok, so just to double check and be sure I don't misunderstand anything before messing with sysNAND... I ran godmode9 (on luma3ds 11.0, b9s 1.4), created this sysNAND backup while on o3DS 11.16 firmware, and will update my fw to 11.17. Then if I, for any reason, ever wanted to downgrade my o3DS sysnand firmware back to 11.16, or any other fw version from backups I made in godmode9, I just follow this gm9 usage guide to restore this sysnand backup (or any previous fw version backup), and it would work just fine, as if I never updated to 11.17?

I don't know if there's something else that makes simply restoring a previous fw version sysnand backup after updating the fw not work. I just remember it being that "easy" to downgrade your fw with the hardmod (just overwrite nand with your backup), but then b9s and Luma made it possible to back up the nand without hardmodding. Does what version of luma3ds, b9s, or godmode9 you had when making older backups matter?

And thank you for the clear reply, KleinesSinchen.

 

[KleinesSinchen]

There is nothing really troublesome with going down a single version. I've done it a lot of times for testing purposes.
Some people are worried about the number of write cycles on their NAND chip, but I expect 3DS consoles do die of something else before. Write cycles do become a concern when writing a fully image daily.

Restoration of very old backup can interfere with Home Menu extdata – as I said before – and the installed titles database gets replaced with the old version, which means some installed software might not show up (or with an X greyed out in Data Management → FakeTik)

 

[DChronos]

There is nothing really troublesome with going down a single version. I've done it a lot of times for testing purposes.
[snip]

Ok, thanks for letting me know, since I did add a bunch of titles on 11.16 when the eshop was closing. Does it store what titles you have installed on another chip or the sd card or something? And if I did go back further than when something was installed, can I just delete the greyed out X in data management and reinstall it from the eshop later, or is there a way to fix it without using the eshop?

Sorry to ask so many questions, KleinesSinchen, I just want to know as much as possible if I ever did want to revert an update or go back, so I can fix any issues that arise.

 

[DChronos]

Was hoping you could let me know about the 2 questions above, KleinesSinchen, or anyone, so I know in advance if I do restore an older backup. If I did ever do this, I'd restore both nand and the sd card at the same time, I back both up.

 

[Hayato213]

Was hoping you could let me know about the 2 questions above, KleinesSinchen, or anyone, so I know in advance if I do restore an older backup. If I did ever do this, I'd restore both nand and the sd card at the same time, I back both up.

If you restore your nand to an early state, your save and games installed would be from that time when you did the nand backup.

 

[The Real Jdbye]

Ok, thanks for letting me know, since I did add a bunch of titles on 11.16 when the eshop was closing. Does it store what titles you have installed on another chip or the sd card or something? And if I did go back further than when something was installed, can I just delete the greyed out X in data management and reinstall it from the eshop later, or is there a way to fix it without using the eshop?

Sorry to ask so many questions, KleinesSinchen, I just want to know as much as possible if I ever did want to revert an update or go back, so I can fix any issues that arise.

Tickets are stored in NAND, you can manually dump the tickets before restoring and inject it afterwards but there is no need since running FakeTik will take care of the missing tickets.

 

[DChronos]

Thanks again, all. Will have to look up FakeTik later. So, I assume if I restore the nand and sd card both to the same date/time backups, then everything will be exactly as is was at that point in time, including any menu extdata, and shouldn't show any greyed out installed titles with an X, since the nand and sd data should be synced to that point in time.

And the file "essential.exefs", is that something I'd only need to create once and I can use this file with any nand backup I made in godmode9, or is this file unique per nand backup or unique to each version of the app? Wondering cause I didn't make a new essential.exefs every single backup, but have several.

 

[Kwyjor]

Wondering cause I didn't make a new essential.exefs every single backup, but have several.

You can easily verify whether they are duplicates using any handy checksum tool. For instance, you can add them to a .zip file and compare the CRC32, or use certutil to compare the md5.

 

[anotherthing]

Another reason it might not be a good idea is that Nintendo is pulling the rest of the 3DS servers here in a few weeks, aren't they? I don't think there's any way to go back to 11.17 without Nintendo servers. Maybe I'm wrong about that, so if anyone knows another way to upgrade from an older version to the newest one without those servers, I'm all ears.

 

[Kwyjor]

Nintendo is pulling the rest of the 3DS servers here in a few weeks

No, they're only ending online services for all games aside from Pokemon Bank or Pokemon Transporter. The eShop is going to remain available for downloading previously-purchased titles for the foreseeable future, and I very much doubt they're going to take down the update server (even if they don't release another firmware update after 11.17 – and who knows, maybe they will).