Living in in hot hot Arizona, the common problem of C70 headliner detachment is unavoidable. Now I've been one to stop the top on my 2008 C70 partially open frequently, and usually without problem, but for longer periods of times, it brings problems. To repair my headliner, I'm using ratchet straps to secure the headliner up while using a High Heat Epoxy to resecure the headliner. I left my top open for too long to throw the straps around, and was faced with the dreaded Top Malfunction Service Required warning, and no matter how much forum digging, button holding, and panel shifting I did, I could not get the top to move. I was about to reach last resort and pull the pressure release cable below the back seats before I tried this:

(Note, this may not work if your top has sensor issues or something stopping the top from normal operation, just deliberate stops like mine)
1.) Disconnect battery: I removed the negative terminal for a decent period of time. about half an hour should do it.
2.) Start car: Reconnect and startup. There should be no immediate top malfunction warnings, but your case may vary.
3.) Brake and hold close: I can't remember if I got a different Top Malfunction (amber ! instead of red triangle) warning without a chime here, but after holding for 5 seconds, my top actually started to move for once (as other forum posts stated should happen).
4.) Correct as necessary: My top did not immediatley latch at the front or move the cover on the trunk lid right away, so the closing operation was incomplete. I pulled the battery again for a minute, reconnected, and then tried the open top function. Once I confirmed everything was moving normally again, I switched to close halfway through and managed to get everything latched up properly like nothing had ever happened.

You may need to hold the trunk lid open somehow through this process until step 3 or 4. If somebody can help out with assisting the roof panels, it's a great help. My first time having this problem months ago, I just needed to raise the deck lid to get things moving again. This time, however, was quite a frustrating event. Hours spent in the heat with an inbound monsoon threatening everything, forum digging with dreads of having to go to a dealer. Everything about this experience has made me feel the need to create an account to share this experience so that hopefully somebody else out there in this unfortunate circumstance can find a way out.

I will also post what I believe is the correct way to fix the headliner on your own while dodging this problem. This is my first forum post. Thank you guys!