I would like to zero-out all data and re-install Lion on my Macbook Air. After booting into recovery mode and running disk util - it seems that I can only "erase" the flash drive. The "security options" button which is normally used to zero out the disk is greyed out. Any clues? I'm wondering if this is due to the way TRIM works when writing to a flash drive and it is no longer needed. Any help appreciated.