NAND restore with different firmware version

[Day]

Hello community,
I'm a day1 SX user and not a native english speaker, so please be kind
I recently decided to restore NAND of my 1st unbanned Switch because I'd like using EmuNand on it to exclusively play offline and leaving the OFW as older as I can (my 2nd unbanned Switch is already running EmuNand and OFW is up to date to play online).
On my PC I've found the NAND backup and now I have some doubts I can't answer:

• Maybe I backupped the Switch (NAND was clean) from firmware 4.0.X and after I updated it to 5.1.0 officially (NAND still clean). Then I installed CFW and from that moment onwards I only used ChoidujourNX without burning fuses. Since I don't know if fuse count is different between 4.0.X and 5.1.0 and assuming it is, if I restore NAND to 4.0.X is there a way to update it to 5.1.0 offline which also leaves NAND clean?
• More in general is there any way to read firmware version from NAND backup files?

Any help is appreciated! Thanks!

 

[Icarium]

Hello community,
I'm a day1 SX user and not a native english speaker, so please be kind
I recently decided to restore NAND of my 1st unbanned Switch because I'd like using EmuNand on it to exclusively play offline and leaving the OFW as older as I can (my 2nd unbanned Switch is already running EmuNand and OFW is up to date to play online).
On my PC I've found the NAND backup and now I have some doubts I can't answer:

• Maybe I backupped the Switch (NAND was clean) from firmware 4.0.X and after I updated it to 5.1.0 officially (NAND still clean). Then I installed CFW and from that moment onwards I only used ChoidujourNX without burning fuses. Since I don't know if fuse count is different between 4.0.X and 5.1.0 and assuming it is, if I restore NAND to 4.0.X is there a way to update it to 5.1.0 offline which also leaves NAND clean?
• More in general is there any way to read firmware version from NAND backup files?

Any help is appreciated! Thanks!

You can inspect the firmware of a NAND backup using this tool. There is another method using Hacdiskmount, but it is rather involved.

 

[Day]

You can inspect the firmware of a NAND backup using this tool. There is another method using Hacdiskmount, but it is rather involved.

Thanks a lot for the information, I'll try it asap. Should I find out the backup is from 4.0.X is there a way to restore it and then update firmware to 5.1.0 someway in order to put on a working firmware according to the fuse count?