I have tried this on Verizon Moto E devices with and without the Android 5.1 update. I have also run this on a Windows and Mac OSX machine. I have used T-mobile(US) and EE(UK) sims.
Everytime you swap the sim with the Android 5.1 fix, you need to re-run the adb commands.
adb shell (adb killserver to stop the daemon).settings put global preferred_network_mode 9
settings put global preferred_network_mode1 9
settings put global preferred_network_mode2 9
get instead of a put and remove the valuePreffered network type should be 4G.