I've seen a few methods how to get root access on latest .253 firmware, but this one is, I think, the easiest way available:
1. If on .253, use flashtool to flash an older version which has available OTA for .253. The one I used is: http://forum.xda-developers.com/show....php?t=2223827
2. Root is as simple as it gets with: http://forum.xda-developers.com/show....php?t=1886460 . Use 3) option to root.
3. When rooted enter "Superuser" and check "ota rootkeeper".
4. After 3. is done go to settings > apps > all > update center > clear data, to avoid force close error, then enter "update center" app on your phone and hit refresh button to get OTA .253 update notification. Download and install latest firmware.