How to: Mods Stainless Steel and 1648 on Steam Deck/Linux

[depapier]

Turns out the mods work. Stainless Steel is probably most interesting for everyone, but 1648 is great as well and shows that the method is universal.
Installing the mods: Either install on PC and move the folder with mods to Steam Deck/Linux environment or use Lutris/Wine/Bottles/Proton to install the mods using their installers into the steam game directory. Obviously this needs to be done in Desktop mode on Steam Deck.
Launching the mods:
1. Some mods, like Stainless Steel, have a setup with custom options. These work fine if you add these to Steam as a custom app and use Proton for compatibility. Alternately, you could use Lutris/Wine/Bottles to launch that setup. Should work fine with either one.
2. The main issue with launching the mods through their own executable is they crash no matter what. However, there is a way around this: in Steam itself open the properties of the game and look at the launch options. Set the first option as Play Total War: Medieval 2 - Definitive Edition. Then look at the advanced input line: here you should add the mod parameters. In the case of Stainless Steel mod, you should add the following line:

--features.mod =mods/SS6.3

Basically, any mod can be added in this way, but be sure to write the folder name exactly.

3. Have fun.

There's another, more detailed guide you can see at https://www.crstanier.co.uk/journal/18-installing-stainless-steel-medieval-total-war-mod-on-steam-version-for-macos

[Shadow of the SPQR]

I've gotten the mods to work before but I don't recall if I ever got the config settings local to the mods to work. I don't think they do with the features.mod option but I'm not sure. What would be interesting is if the engine extender mod worked on linux, which I know was built exclusively with Windows in mind. If that works, linux modding is up to speed and 'in the game' for real.

[depapier]

From what I can see the mods work fully with this method. It's nothing but inserting command line arguments, which is what mod executables do already. All of this is valid only for windows version that's run through Proton, not the native Linux version. Idk what the engine extender mod is.

[Shadow of the SPQR]

Originally posted by depapier:

From what I can see the mods work fully with this method. It's nothing but inserting command line arguments, which is what mod executables do already. All of this is valid only for windows version that's run through Proton, not the native Linux version. Idk what the engine extender mod is.

I was attempting through the Linux version, which has a few tweaks for improvement but is also where the caveat comes in modding. Most useful would be getting most mods to work through that client since it is default for linux users. The engine extender is used on an increasing number of highly ambitious mods looking to go past traditional game limits, such as Elder Scrolls TW.

[depapier]

Right, but since you can get the windows version work very well via Proton, I don't see an issue with that. I'm curious to try those extended mods out. Any suggestions apart from elder scrolls one?

[Shadow of the SPQR]

Originally posted by depapier:

Right, but since you can get the windows version work very well via Proton, I don't see an issue with that. I'm curious to try those extended mods out. Any suggestions apart from elder scrolls one?

I know there's more that use it but unfortunately there is not a clear coherent list. I think Age of Petty Kings uses it for stability, and some of the heavy-duty fantasy mods besides ES do it as well (though they have other stability issues; Warcraft TW, Hyrule TW). I'm sure there are historic mods which use it but I can't name any at the moment. Someone else might know.

[Gigantus]

The thing with using the command line entry is that it completely bypasses all other CFG file entries of the mod, some of which that are intentional, like hiding battle banners. But you can add more command line entries using this method:

This command line:
--features.mod=mods/SS6.3

equals this entry in the mod's CFG file:
[features]
mod =mods/ss6.3

The first part in the command line is the bracketed entry, followed by the individual line.

Example for 'always reinforcements':
[game]
unlimited_men_on_battlefield = 1

--game.unlimited_men_on_battlefield=1

Note: no spaces in the command line!