Critting uncritable favored enemies?

[Sintanan]

I thought I came across a series of feats that unlocked the ability for Rangers to achieve critical hits on their favored enemies even if the favored enemy is normally uncritable (like Undead, Plants, etc).

At least, I remember reading about something akin to this one time, although I cannot remember the source. Can anyone confirm/deny whether or not there is a special ability/feat out there that does this?

I was thinking about rolling a crit-focused TWF Ranger.

[sonofzeal]

You may be thinking of "Swift Hunter". Your Scout and Ranger levels synergize, and you can get precision damage on many things that are normally immune, if they're your favored enemy. Nothing about crits though.