I've been ranting about this in the D4 ICS leak thread...my worry that the ICS update for the Droid 4 will break the ability to go into the Mobile Network Settings menu and turn OFF 4G (CDMA Only). I do this, as many others do, to save battery life when I'm away from a charger or power source for a long time.
The screenshots in the ICS leak thread show three settings: Global, LTE/CDMA and UMTS/GSM, with no separate option to switch between LTE/CDMA and CDMA Only.
I think I've figured it out, with help from some friends in another (non-Android-topic) forum.
It is not necessarily ICS itself that does this. It's the capability to do global roaming, which is apparently bundled into the 4.0.4 update for the Droid 4, the Droid RAZR and the Droid RAZR MAXX (the last two are now released).
Fortunately, there's a way around it.
The app LTE OnOff, which is in the Google Play store and says it's for the HTC Thunderbolt, will also work on the D4...and as I've been shown, post-update on the RAZR/RAZR MAXX. (I don't have the ICS leak for the D4.)
Instead of popping up a direct menu, the LTE OnOff app on the D4/RAZR/RAZR MAXX pops you into the phone's internal phone info screen.
Scroll down until you can select networks...open the menu and select one of these:
GSM/CDMA only (PRL) - for 4G/LTE
CDMA only (PRL) - for 3G
*** CAREFUL HERE, I DON'T KNOW WHAT THE OTHER OPTIONS DO! *** If your phone stops working because you hit the wrong menu option, select the right one...but I'm not responsible if it doesn't work after this! It should be OK, though.
After selecting one, just let it flip in a few seconds. That's it!
On the D4/RAZR/RAZR MAXX, LTE OnOff takes you to the same internal menu as this phone keypad code:
I hope this helps someone. I asked, and asked, and Google searched, and asked, and it took all that to get to this point.