Homebrew Is it possible to backup a game update, then use it to downgrade later?

[AkiraKurusu]

Fire Emblem: Three Houses just received its 1.2.0 update, but I'm still on 1.1.1 because I've got working cheats and a save editor for it.
Is it possible to backup the 1.1.1 update, then use it to downgrade back to it should 1.2.0 prove undesirable? If it is possible, how would I do it?

Of course I'll backup my save data first using Checkpoint, so save corruption's not an issue.

 

[TunaKetchup]

I think Tinfoil allows you to delete game updates

 

[TunaKetchup]

nxdumptool can dump your update to a nsp file

 

[AkiraKurusu]

I know that Goldleaf can delete updates and tickets, but I've never used Tinfoil or nxdumptool.
And reinstalling updates?

 

[TunaKetchup]

I use SX Installer but for other CFW it seems lots of people use Awoo https://github.com/Huntereb/Awoo-Installer

 

[shadowkillerdrag]

You can install the 1.2.0 update. If it doesn't work.
Use Tinfoil -> Delete Update -> reset the update ticket ( so there is no popup when you start the game) -> install 1.1.1.

 

[AkiraKurusu]

So...nxdumptool's asking for a "keys file"; can I just use the Lockpick app (which gets keys 00-05, apparently), or do I need to use Lockpick_RCM to get "newer keys"?

Also, what do I dump? ExeFS dump? RomFS dump?

...I'm brand-new to nxdumptool; forgive me.

 

[AkiraKurusu]

Oh, so I'm guessing it's one of those "missing base application" hidden things in NXDumpTool?
Fire Emblem: Three Houses v262144 (010055D009F78800) (Update)? Followed by NSP dump? I think I do have to use Lockpick_RCM, since it apparently doesn't have the right keys...