I've gone all the way down to Alftand Cathedral, but when I try to activate the dwarven mechanism to go to Blackreach it says that I lack the required item ie the attunement sphere.

Can I do a cheat code so that I don't have to go all the way up again? What should I type?

Thanks.

There is a lift right there that takes you directly back to the surface.

coc BlackreachCity

coc BlackreachOrigin

coc BlackreachArena

I've never done this so I don't know which of these three cells is the main cavern. You may have to experiment (save first). Also, it's possible that bypassing the quest that grants you the key to the lift may interfere with something in Blackreach later on. With that said, one of these will get you there.

I'm unsure what to do but going back to the surface, even using the lift, is futile. You see, I have already done Septimus Signus' quest, and it is he who should give me the attunement sphere needed to open Blackreach. And the other Sinderion guy who has another sphere is inside Blackreach so I can't go to him either.

I can't understand how the sphere is no longer in my inventory since it's supposed to be a quest item - I have never used cheat codes in this game... this will be the first time.

Might be simpler to use a code to add the attunement sphere back to your inventory (I'm guessing after the quest is complete you're able to sell it/put it in a chest.) Should be: player.additem 0003532C 1

Thanks valandril, I guess that's the best solution

beat me to it but yeah, console command it back into your inventory and hopefully it works.

Or just console command the required number of roots into your inventory as well