Alt,
I ordered two 64 gig cards off amazon for the about 55 dollar price. I attempted to install them on 905. The first card I immediately reformated from the EXT2 format to Fat32 using a program, and the phone on 905 would no longer see it, nor any of my PC's. I took the second card and installed it directly in the phone, and got the corrupt/reformat menu. I did so and let 905 reformat it. All was good.
When I did the HOB, I had erased all of the media off the card to avoid the several hour media check. But, the phone sat on the media update portion for almost 3 hours. I had read of significant issues with ICS and the 64 card with some phones, so I decided to just kill the update to ICS. When I pulled the card to try and read it in my PC's, the card was borked. I had to reformat it, and now only have 27 gig available on the card.
So honestly I am not sure 100% it was ICS, but it was working fine in 905. And I am not compltely sure if the media update portion of the ICS install actually reformats the card or just goes through all of the files, but something did happen to me. There were very few media files on the card, so I was just guessing that after about 3 hours of waiting, I was truely "hung". If you want to get really confused, try reading the reviews of the various 64G card suppliers on Amazon. My next card will probably be full retail from a trusted source. I did learn that the first thing to do when getting a card is confirm exactly how it is natively formatted before making a decision as to proceeding.
Craig