Hacking A9LH NANDmin.bin/sysnand backup and different nand questions

[Inflameslol]

So Ive been a gateway into gatewait+reinand user since a year or two back.

I did the switch to A9LH 2 days ago and I'm waiting for my 64gb mSD to arrive.

I have a few questions regarding nand backups. what they are exactly and what each is used for.
back on the old emunand setup, there was emunand and sysnand .bin backups

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Questions:
1. When we use the plailect's guide to downgrade to 2.1 using ctr transfer we do a backup which gets us NANDmin.bin - this happens once again when we go from 2.1 to 9.2 deciding to use a fresh install(guide says to backup once more, we retrieve another NANDmin.bin). Are these two NANDmin.bin exactly the same? or do they differ in any way shape or form? Im asking because maybe the version your 3ds is/was at might change the backup or the way the backup gets used.

2. Once A9LH is set up and its running fine..If I got to hourglass/decrypt9 and do a sysnand backup I get what I assume is a regular sysNAND.bin backup (similar to the sysnand you backup on my old emunand setup). What are the differences between these methods of backup and the difference of the files? I am very confused.

I'll try to explain what I mean with differend nands

9.0->2.1 ctrtransfer -> retrieve 1.21gb NANDmin.bin
2.1->9.2 ctrtransfer -> retrieve another 1.21gb NANDmin.bin

A9LH is done setting up;

Decrypt9WIP sysnand backup -> retrieve a 1.84gb NAND.bin file

Hourglass9 sysnand backup -> retrieve a 1.21gb NAND.bin file

edit: i forgot to mention that for all 4 backups I did get a bin.sha with them too.

I have a feeling that the one made through ctr transfers plus hourglass9 is exactly the same due to being the exact same filesize in bytes

Im asking because I dont want to accidently delete one of them only to realize I mightve needed as specific-made backup later down the road.

 

[trinhno]

I have a question, why did you do a 2.1->9.2 ctrtransfer? You were supposed to use the 9.2 NANDmin.bin to go back.

Anyway, here's a breakdown:
9.0->2.1 ctrtransfer -> 1.21gb NANDmin.bin, 9.2 image without A9LH, min size
2.1->9.2 ctrtransfer -> 1.21gb NANDmin.bin, 2.1 image with A9LH, min size (assuming you got it after running SafeArm9Installer)
Decrypt9WIP sysnand backup -> 1.84gb NAND.bin file, 9.2 (or whatever version if you've updated before running), A9LH, full size
Hourglass9 sysnand backup -> 1.21gb NAND.bin file, 9.2, A9LH, min size

The size different is because you didn't use min size in Decrypt9. The extra part is just zero. 3DS NAND should fit inside 1.21GB. Physical NAND sizes differ because they source chips from different manufacturers.

 

[Inflameslol]

I have a question, why did you do a 2.1->9.2 ctrtransfer? You were supposed to use the 9.2 NANDmin.bin to go back.

Well I had to double check. "If you do not have any usable NAND backups, follow 9.2.0 ctrtransfer starting on Step 4"
I had been at it for a few hours doublechecking and re-reading the guide as I go and it was really late. I mustve read that nand backup as emunand..or something along those lines.

Alright so if I understand it correctly the only important files to keep multiple backups of is:
the first NANDmin.bin & bin.sha
and the otp file
and the hourglass9 is similar to an emunand backup back when I used gateway emunand

To be honest Im not sure if I made a backup when going from 2.1 to 9.2 with ctr transfer. Because the first time I got an error before step #3. and the second time i fat fingered b to skip the backup. It was already on pc though from earlier when you went to 2.1 from 9.2.

Btw. Do I need to do anything since I ended up doing a ctrtransfer from 2.1 to 9.2. such as a nintendo format or so? idk what happend to my NNID or if anything important changes compared to restoring the NANDmin.bin.

 

[trinhno]

Yeah, the first backup pre-A9LH is important. OTP is of course. Just back them up to multiple places.

No. CTRtransfer is good as the image provided is clean. You can log in after that.