tldr;
Fastboot all 6.12.181 files you can, flash the boot208.img, go to recovery and install the 6.16.208 zip.
If you want to root, flash the boot85.img, root with that (may require BP Tools boot), then flash back the boot208.img and you'll be golden.
Edited by mattlgroff, 01 June 2012 - 08:05 PM.
Renamed files and reuploaded.