[Galaxy S 4 Q&A, Help & Troubleshooting] spotify95:
Hi,

Sorry to bump this but I have the same issue. I have a Galaxy S4 and it is very weird with its network selection.

The default setting is LTE/GSM auto, which I believe is LTE combined with the GSM Auto mode that everyone knows about - this being, prefer 2G instead of 3G in weak signal areas.

I have the following options:

LTE Only

LTE/GSM Auto

GSM Auto

WCDMA Only

GSM Only

WCDMA Preferred

Plus a load of other stuff about CDMA and EvDo (I'm sure that the GT-I9505 doesn't support CDMA or EvDo?).

The problem I am having is as follows:

Immediately when I got the S4, I realized that it was preferring GSM over WCDMA/HSPA. This was confirmed when compared with a Samsung Galaxy Ace Plus, on the same network, in the same location, and the Ace Plus (S7500) was choosing 3G, whilst the S4 chose 2G. Doing a bit of Googling led me to find the WCDMA setting, and after choosing that, the S4 chose 3G.

So all was good for the last 2 years, using WCDMA Only mode on my S4, as my mobile operator (Virgin Mobile) didn't have 4G access. Losing LTE wasn't a problem.

However, now I have switched to the EE network, I now face a problem. As mentioned above, there is the WCDMA Only mode, and the LTE Only mode - meaning that I am unable to have both 3G (WCDMA) and 4G (LTE) without also having GSM, and there is no way that I want to ever use GSM again, especially since that EDGE/GPRS are barely usable as data connections, GSM has sub-standard voice quality, and the S4 is choosing GSM over WCDMA.

A couple of examples, once on my way home, the S4 dropped from 4G to 2G and completely ignored 3G - despite being right next to a 3G mast operated by EE (albeit on the old Orange code). On WCDMA mode, the phone always connects to the Orange 3G mast. Thankfully, a bit later on, it did pick up 4G again, but if I was streaming Tunein Radio, that would have been a disaster (it would have dropped the stream).

A bit later on, on the same journey, the phone also went to 2G, from 4G - despite being in a reasonable signal area for 3G. Why didn't the phone choose 3G? I'd had enough by then and switched to WCDMA Only mode; result? 28% 3G signal (3 bars)!

It's also happened on my local mast, until a few weeks ago. The S4 was choosing 4G from a more distant mast (strength 50%), instead of 3G from the local mast (strength 60%). When I went downstairs, to the kitchen, the signal strength dropped and the phone went straight to GPRS! GPRS is likely to give about 30kbps max, so I don't know why the phone was doing this - although about 20-30 seconds later, it did then go to the 3G from the local mast.

I can't use LTE Only mode as (a) the 4G rollout isn't complete, and (b) the S4 does not support Voice Over LTE (VOLTE), meaning that in 4G only mode, I have no way of accepting or receiving calls.

I need a 3G/4G mode (LTE/WCDMA) on my S4, that doesn't use 2G at all, because 3G/4G signals are present virtually everywhere on the EE network, and it would stop the S4's crazy behavior.

Any suggestions to remedy this would be appreciated. I am not rooted, though if someone knew how to root the phone for me, it could be a possibility, as it is out of warranty.