Could my iPhone 6's 4G possibly be "broken" while its 3G still works? The question sounds strange I know. For the last few days I have not seen 4G up at the top of the display of my iPhone 6; it's been demoted to 3G. 

I'm in the same several locations where I have been, and the signal is always 3 or 4 bars out of 4.

I can't imagine that there are separate chips or antennas for 3G and 4G, so this may be related to my carrier in some way, but I thought I would just check here first in case I'm wrong.

Are there any tests I can do to check this myself? Stand under a tower and use the aluminum foil I normally wear under my hat as a reflector for example? ;-)

My iPhone 6's software is 12.4.3 and I have a notification that 12.4.4 is a recommended update.



Cropped iPhone screen shot (with carrier's name manually blocked out).
Go to settings > cellular data > cellular data options > turn off 4G and turn it back on.

Another way I use to get my phone on 4G is airplane mode on and off.