ns2jb-modloader 0.3.4 loads RomFS and ExeFS mods on Switch 2 from microSD, no CFW involved
SebaaMG has shipped five versions of this Switch 2 mod loader in five days. It runs on top of an ns2jb session and reads each game's mods from the microSD card.
Per-game mods for as long as the session lasts
The loader looks on the microSD card for RomFS and ExeFS mods sorted by Title ID and applies them per game, on top of a running ns2jb session. You start it from the PC with a Node.js script in the package. The exploit underneath is tethered, so everything goes away when the console reboots. This isn't CFW, and there's no support for plugins, cheats or overlays.
The first version came out on November 3. Version 0.3.4, from November 7, improves stability and mod compatibility.
Requirements
You need a microSD or microSD Express card, though the README says Express still needs hardware testing. You also need an RPC session with filesystem access, from ns2jb or another compatible exploit, and a PC running Linux or WSL with Node.js 22 or newer. Building from source takes Zig 0.15.2.
Since 0.3.2, the release notes say SmileBASIC and firmware 23.0.1 aren't fixed requirements for the loader.
Testing so far
The 0.3.1 notes mention a real Switch 2 running Mario Party Superstars, Super Smash Bros. Ultimate 13.0.5 and Mario Kart World. A cache-check warning at shutdown is still being investigated. The GPL-2.0 project calls itself experimental.
