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Recovery from a mistaken dd can be made easier by first doing dd if=/dev/diskX of=/path/to/backup bs=4096 count=8 ... then even if you destroy the partition table on the wrong disk, you can recover it from the backup (by copying it back). I would do that twice, to two separate disks—that way, even if you accidentally hit your backup disk, you can grab the file from the other disk. (BTW: count is essential; without it, it will zero the entire disk)
@R.M. Not much, if any. Put a card in rfmon mode, and capture an association packet, and you have the SSID (even on a hidden SSID network). And you can often force reassociation.