doesnt seem like this is really happening, time to find a older FW Wii U
I did this - I bought a 5.4.0 console when I already had a 5.5.0 one, with the main goal of using Loadiine. In my experience, it's not worth it - I ended up returning the 5.4.0 console a day later, which killed any hype I had for the 5.5.0 exploit.
Some things I didn't realize before buying 5.4.0:
- You can't transfer pre-installed software, downloaded purchases, or savegames from the 5.5.0 system without connecting the 5.4.0 console to the eShop and updating it to 5.5.0 as well.
- The kernel exploit relies on a race condition, i.e. when you launch it, there's a good chance nothing will happen and you will have to launch it several times... and this is every time you want to use Loadiine. I don't know what the IOSU exploit's entrypoint is, but if it's anything like the existing kernel exploit, it will be very frustrating to get it running.
- Games that are not supported on Loadiine v3 (Bayonetta 2)
- Games with unreasonably long (15m+) Loadiine load times (The Wonderful 101, Super Mario 3D World)
- Multiplats that are better on another system (Deus Ex: Human Revolution, Mass Effect 3)
- Games where online is the main draw - which Loadiine can't do (Smash, Mario Kart, Splatoon, Mario Maker)
- Remakes of GC games which you can play on vWii (Wind Waker, Twilight Princess)
- Straight-up garbage that is not worth your time, even if it's free (Amiibo Festival, Devil's Third, Mario Party 10)
Unless you like to tinker with electronics for the sake of tinkering (and have $200 to spare), it's not worth bothering with lower firmware. Just my two cents.