This firmware should be also enabled for non-thunderbolt macbooks.
I have a mid 2010 macbook pro (no thunderbolt) and a late 2008 24inch LED Cinema Display. I staretd having a very bad flickering issue, and this firmware refused to install on my machine (since it doesn't have thunderbolt). I had to take it to apple service center and pay around $70 (minimum inspecation charges). All what they had was a macbook pro with thunderbol port, where this firmware was successfully installed on the LED display. My 24in display is now working with no issues.
This firmware upgrade should be extended to support the older models (with mini-display port) which don't have thunderbolt.
Apple please be carfeul next time and watach out for such pitfalls (which costs me $70).
LED Cinema Display (24-inch), Mac OS X (10.7.4)