The 1.1 Update and the DLC patcher for Smash Ultimate, unfortunately, requires 6.2.0 ofw to verify NCA signature with master key 6, which is non-existent in 6.1.0. Which is why some may have noticed if using tinfoil on 6.1.0, a booterror for missing key.
I use SX OS too consistently to forsake it to bump up to 6.2.0, plus i currently have most of my data consolidated to SX's Emunand, and still am unsure whether just renaming the Emutendo folder to Nintendo, and removing the original nintendo folder, will preserve all my emunand save and content data if persay I was to run Atmosphere primarily on sysnand instead... I likely will eventually make the full commit to Atmosphere though, as SX is far too slow behind the curve on firmware updates. CTCaer and Rei even put them to shame and they've been almost dark about eta the past couple weeks... le sigh.
In any case, Smash on. I do eventually want to crack into that DLC content..