With the introduction of the new version of the Android operating system "Android 4.4 Kit Kat", some users have found that when using giffgaff, O2 or Tesco SIM cards they no longer have access to the "2G ONLY" mode (found in Settings > Mobile Networks > Network Mode), but instead only have the "4G" and "3G" options.
We've found that the "2G ONLY" mode DOES appear if using other networks' SIM cards so the issue seems to be restricted to Android 4.4 on the O2 Mobile Network.
We believe the only affected devices will be those that are upgraded to Android 4.4 (Kit Kat). The following is a list of devices that could get this upgrade, and therefore could be affected by this issue.
Now: LG Nexus 5 [update 18Aug14 Nexus 5 now has "2G preferred" option in normal settings which actually sets 2G only. This is part of Android 4.4.4 Kit Kat)
Samsung Galaxy S5 [added 18Aug14]
Very soon: LG Nexus 4
Asus Nexus 7
Samsung Nexus 10;
Expected in future: Samsung Galaxy Note 3
Samsung Galaxy S4
Sony Xperia Z
Sony Xperia Z1
Motorola Moto X
"End of January": HTC One
HTC One Max
HTC One Mini
Possible but nothing stated formally yet:
Samsung Galaxy S4 Mini
Samsung Galaxy Nexus
Huawei Ascend P2
Huawei Ascend P6
ZTE Blade V
ZTE Blade 3
Acer Iconia A1
Acer Liquid S1
It's also worth noting that the issue might not be present on those phones with an added User Interface Overlay, like Samsung's TouchWiz or HTC's Sense.
"Why would I want "2G ONLY" mode set?"
For those users in a weak 3G/4G signal area, a stronger 2G signal often gives a better user experience for voice calls than a weak 3G/4G signal. In these cases forcing the phone to "2G ONLY" will prevent the phone switching to the weak 3G signal, which can result in a better user experience. If you have good 3G signal, you likely won't need this option.
So, if you need the "2G ONLY" option and it isn't listed in "Settings > Mobile Networks > Network Mode" what can you do?
Firstly, know that giffgaff are in talks with Google and O2 trying to remedy the issue, which should add the option back into the normal settings screens, however for those that need the "2G ONLY" option now, there is a work-around:
NOTE: This guide takes you into a development menu that isn't usually accessible. While your phone shouldn't come to harm from following this guide, neither myself or giffgaff can take responsibility for any undesirable consequence of using this menu to alter your settings and you do so at your own risk.
It's also worth nothing that changing the settings in the following guide can switch off your data connection temporarily so if your phone is your only way of accessing these forums make sure you follow the guide carefully.
First, we need to access some special hidden settings in the phone.
We can access this screen in two ways: by installing an app from the Play Store, or by manually entering the menu.
The app I use is called Radio Switcher. You can search for it or others like it on the store, or follow this link to grab it directly.
If you want to load up the menu without an app, it's easy - just use your phone app to dial the following:
You don't need to press the Call button as the hidden menu opens after pressing the last *.
You will see this screen:
Press "Phone information" to get to the settings we want. You will see the following screen (this is also the screen the Radio Switcher app opens):
Ok, now we are where we can change to the "2G ONLY" option, but first it is wise to screenshot the bottom of this screen where the options/settings are. Scroll to the bottom of the screen and do a screenshot (by holding powerand volume_down at the same time). This will help you reset back to default settings if you change something you shouldn't. You can find this screenshot in your Gallery app later if you need.
The only setting we need is the "Set preferred network type:". The others can affect how your phone operates, so be careful not to press anything you don't understand.
For the Google Nexus 5 handset the default is "LTE/GSM auto (PRL)" but my old HTC Desire bravo was "WCDMA preferred"
If you have Android 4.4 on a non-4G LTE phone the default might be "WCDMA preferred",
Either way, if you want the "2G ONLY" setting you need to press the default option to get the drop-down menu, and select "GSM only" which means the same as "2G ONLY"
As you can see, the "Set preferred network type" is now "GSM only".
You are now in "2G ONLY" mode and your phone wont try to connect to any 3G or 4G signals. To revert back just change that setting back to the default "LTE/GSM auto (PRL)" or "WCDMA preferred".
Happy giffgaffing :-)
This is an informative post, however I suspect it will be of limited value to most users. As can be seen from the screen shots in the OP the terms used are LTE/GSM auto and WCDMA preferred. When these faster networks are unavailabe 3G / 4G hands off automatically to 2G services anyway. I've read a number of articles on this issue and while there COULD be benefits there may also be draw backs. Calls on GSM require a specific data rate for a connection to the cell tower for both the outgoing and incoming part of a call. If these are not achieved the call drops. Whereas 3G sends the data in packets which requires a much lower data rate. So even if the 3G /4G signal is weak it may still connect the call. Just my two penneth.
I'm not sure how much benefit this fix offers.
My Nexus 5 still connects to 2G when that is all that is available anyway. Admittedly I don't live in an area where only having 2G is a constant problem but so far I haven't noticed my voice calls being badly affected when I'm out of range of 3G services.
Anyway thanks for taking the time to post this it's educational and it may benefit some people.
I wonder if non Nexus phones will be affected when they upgrade to KitKat. The 4.4.2 update hasn't fixed this issue either.