Originally Posted by simobile
It's the other way around.
Rom updates will alter that file. Radio updates won't have any change. That file tells the radio how to interact with the phone audio inputs/outputs. This is designated by the rom. Your best bet for right now is to use this method: http://forum.xda-developers.com/show....php?t=2234143 It'll make it quick and painless for you. A zip would be nice though. I'll try to cobble something up this weekend. Not gonna have enough time in the evenings this week.
Here is a recovery-flashable zip that does the following:
1) renames /system/etc/snd_soc_msm/snd_soc_msm_2x_Fusion3 to /system/etc/snd_soc_msm/snd_soc_msm_2x_Fusion3.bak
2) replaces the snd_soc_msm_2x_Fusion3 with the stock JDQ39 snd_soc_msm_2x_Fusion3 file with the changes to lines 1804 and 2736 as you described here
I have no way to test, as I am not with T-Mobile, but the zip should make the proper changes.
All credit goes to simobile.