Hi, i'm new to android phones (am familiar with Honeycomb on my xoom though), just got my pre-owned nexus s in the mail yesterday. It came unlocked and rooted (I think) because when it boots up there is the unlock symbol, and in my apps i do have superuser. I don't see a clockworkmod app though. My problem is I wanna unroot it back to stock, then re-root it again so i can install custom roms such as ICS. So whenever i go into the bootloader, select recovery, i get the exclimation point in the triangle error. i press vol up and power and get some options, but only wipe data / reset ect. nothing like what i've seen in the youtube vids. my guess is that the previous owner updated to gingerbread 2.3.6 and may have replaced some files??? i don't know. Any tips on how i can unroot without any recovery files? thanks!