edit: Moved to aokp thread since that's what I'm running.
Edit: Moved back since the quote doesn't exist in that thread
If for some reason you have to toggle data. Toggle to "GSM Only" wait for the 3G or 4G symbol to come on, then toggle to "LTE/GSM/CDMA auto (PRL)"
This isn't working for me lately. I've tried this several times and I get back 3G but not 4G. In a wild frenzy to get data back, amid reboots and toggling, I went to LTE/CDM auto (PRL) in the testing menu, all of a sudden 4G came up perfectly. Is it possible there's some sort of menu index mismatch between the testing menu, network menu and the toggles? Each time I went in it seemed like the different menus had a different opinion on what the actual current setting was (like right now with data working, the testing menu says LTE/CDM auto (PRL) but the network menu has no radio button highlighted, a couple other times through they were showing different things).
edit: weird obvservation; I'm back to 3G, I look at the toggles and LTE turned itself off magically. I slide LTE back on, and go into the testing menu and I'm set up as GSM/CDMA auto (PRL) and network mode is set LTE/CDMA. I think it's time for me to pull code and poke around, this feels like the different apks/portions of the OS all have different takes on what the internal option value should be.