Morning @navilite, @MrSquishie, @Adam Walter, @BenF, @Richard Gaskell, @NorthStu, @SBreeze, @ked239,

Have you tried the Dial Code: *#*#4636#*#*?

In the Phone Information menu, there should be an option to Set Preferred Network Type" to "LTE-only" (4g), LTE/WCDMA (4G/3G), NR/LTE/WCDMA (5G/4G/3G).

I haven’t been able to test this myself as I use an iPhone, so let me know how you get on!

Thanks.

Tried dialing that, it says "your service does not allow access to this number"

Thanks

Ben

@Matthew T @Kash 

It’s the team that manages your carrier/operator/network settings (perhaps called IMS) with Google/Android or as you are an MVNO, your tech contacts at Three who can make this change.

You can see my phone last received a settings file dated 2024-02-28 from ID Mobile (idmobile_gb) in the blue circled bit below. This is later than the one I originally received so someone within iD Mobile knows how to issue / authorise these carrier updates and is doing so. The settings for WiFi calling and VoLTE calling will be captured within these carrier settings in case that information helps you identify the right people to speak with.

All we want is the restriction removed on us being able to use the “Allow 2G” toggle on our phones. You can see it is greyed out below due to iD’s carrier settings. At the moment, iD force us to have 2G enabled (even though Three’s network does not support 2G as you say) whereas we just want the ability to turn off 2G support that our phone already gives us if iD mobile had not restricted it with the operator settings file.

The equivalent on an iPhone is I think if you go to Settings, General, About and look at Carrier (or Network Provider depending on ios version)  … it will have the name and then a version number after it.

Afternoon all,

I have checked in with our partners at Three UK who have said the following:

“This situation cannot create a security issue. Three does not have any 2G network and so all devices cannot attach to 2G while a Three/iD SIM is inserted, irrespective of what device config is set. It’s a non-accessible legacy indicator as there is no 2G connectivity/options actually utilised. Some roaming territories do have 2G Voice enabled (not Data or SMS, Just Voice) and so if these devices are attached in these territories to a network with 2G Open and detectable by the device, then the toggle would be available to switch off.”

Thanks.

That is a very interesting response @Matthew T , thank you for following up and posting the direct quote. Thank you to Three UK for answering so candidly.

Reading the above in conjunction with Google's Security Blog, an example:

If I was in an area of the UK with no Three UK signal and I walked past a false base station (FBS) advertising one of the roaming territories networks with 2G Voice enabled, my Three/iD SIM would connect on 2G but only to send/receive voice, not data or SMS as Three UK imply that the SIM is restricted to only use a 2G FBS for voice despite encountering a FBS advertising whatever it wants.

Further Three UK are implying that there is no known exploit of 2G Voice and therefore everything is good enough from a security point of view with the setting as they have it even though the 2G feature of a phone’s modem is still enabled when it does not need to be. (You can imply this from “there is no 2G connectivity/options actually utilised”)

Possible improvement

I guess the obvious improvement is for iD/Three to work with Android/Google so that the “non-accessible legacy indicator” could remain greyed out but be shown as disabled (2G not allowed, 2G feature of modem turned off) rather than enabled (as in above screenshot) when a Three/iD SIM is inserted and then no-one will be confused and asking questions. 

The text underneath the greyed out toggle would then say something like “iD requires 2G to be disabled” where it currently says “iD requires 2G to be available”. When Roaming is toggled on, see toggle near top of screenshot, it could trigger the 2G toggle being available to cater for the roaming territories with 2G Voice enabled.