[Epic 4G Android Development] AmericanJedi001:
Introduction

This is the optimal method for reducing and almost eliminating rotation lag in EpicMTD CM7. For those of you looking for the old method that involved hacking framework.jar, please see the second post in this thread, Deprecated (Old, Archaic) Rotation Lag Fix How-to

DISCLAIMER

I have personally used this method and know it works. Furthermore, many others have used this method and it seems pretty reliable. That said, should anything unpleasant happen, to include bugs being introduced, your phone bricking, or your firstborn child emerging as the anti-christ, well, it's not my fault. You did it.

Rotation Lag Eliminator Guide

If you have a ROM setup that you're fond of, or high-scores that you want to keep, I recommend doing some backups

Nandroid from ClockworkMod Recovery ("CWM") will backup your entire ROM, which you can restore after the fix and have your phone back to the state it was in before you made the backup. (Kentucky.)

Alternatively, after step 5 you can restore just the /data partition from a previously-created Nandroid backup.

Titanium Backup can back up & restore individual apps and settings, as well as restore from a previously created Nandroid backup.

Flash a GB ROM (not sure if it must be MTD, but I recommend it), I recommend toadlife's Clean-GB MTD

Go to [Settings] > [Display] > [Horizontal Calibration]

Calibrate. (Obvious, no?)

Flash your favorite EpicMTD CM7 Nightly, AKA the latest one. (You know I'm right!)

Think to yourself "That AmericanJedi001 just might be a genius. He damn sure knows how to fix rotation lag!"

Immediately follow that with the self-rebuttal "Yeah, but it's not like this required anything previously unknown in this community."

Caveats & Notes

Slight risks are involved in flashing ROMs and backing up and restoring Nandroids and individual apps.

This fix should persist across ROM flashes, and therefore Nightly flashes. There may be something that breaks it, but I haven't found it yet. (I'm not trying to break it, but I don't know where the calibration data is saved, therefore I don't know what mods will break it.) I suspect that either a) switching minor versions of Android, such as going from Froyo / 2.2 to Gingerbread / 2.3; or b) switching partition maps, such as going from BML to MTD, is what breaks it.

Thanks and Acknowledgements

Thanks to Decad3nce for pointing out that not everyone has had issues with rotation lag in EpicMTD CM7, which got me to thinking that the framework.jar hack might not be the optimal fix.

ISSUES / PROBLEMS / BUGS?

I'm reluctant to provide any active support for this fix because all of its steps are well-known and -documented elsewhere. That said, if you have any issues that you think are specific to rotation-lag elimination, post 'em here. If you post something in the vein of "I flashed blah-blah-blah and now my phone figuratively resembles a brick..." or "Why won't my backup restore?" I'm going to ignore you, because that's not specific to this fix. Those questions have been beaten like Jim Caviezel in Passion of the Christ, and like his character sometimes I wonder how they're not dead yet. Please use good judgement before you look for help here.