Android is not letting me select preferred network type to LTE for my 4G SIM, because I have selected the other SIM for data. The thing is, it only lets you select LTE as preferred network for a SIM which is selected as your DATA SIM.

The problem is the 4G SIM that I have, doesn't work on any network other than LTE. So if I am using data from my other SIM (3G), the network for my 4G SIM is gone.

Is there a way around it?

  • 1
    normally in dual sim devices even if it is LTE capable only 1 SIM card can access LTE the other 3G, I'm suspecting since you chose a second card for DATA then the other which is LTE only can't work - must be a carrier/android restriction there Mar 17, 2017 at 12:23
  • @xavier_fakerat Yes, only one SIM card can access LTE, but it doesn't depend on the slot it is in. The data SIM is only allowed for LTE. Now, I am using data on 3G SIM, and I have changed it's preferred network type from LTE (recommended) to 3G, it should in theory then let me select LTE for the other SIM, because I have told it to not use LTE for my 3G SIM.
    – Shanks
    Mar 17, 2017 at 12:27
  • @xavier_fakerat : This is the correct answer, make it a valid answer.
    – M. A.
    Mar 17, 2017 at 12:28
  • @ Abdelhafid Madoui , Ok just edited and put it in answers section Mar 17, 2017 at 12:33
  • @xavier_fakerat : I agree there is a restriction. But it's only software that's restricting it, not hardware. So manually choosing 3G for my data SIM should let me have LTE for my 4G SIM in theory.
    – Shanks
    Mar 17, 2017 at 12:44

3 Answers 3


In any 4G enabled dual SIM handset, only one slot is meant to support LTE, that is SLOT 1.

Insert your 4G SIM in SLOT 1 and 3G SIM in SLOT 2.

  • No, it doesn't work that way. It doesn't depend on the slot. It depends on what sim you have selected as your data sim. I am able to get LTE network for my 4G SIM irrespective of the slot it is in, provided it is selected as the data SIM.
    – Shanks
    Mar 17, 2017 at 12:38
  • This is wrong, Dual SIM phones are able to switch between SIM cards, if your data connection is used by the second card it will get the support for 2G, 3G and LTE and vice versa.
    – M. A.
    Mar 17, 2017 at 12:46
  • In dual SIM handsets, you can use only one SIM as 4G at a time. So it is preferred to insert your 4G SIM in SLOT1, and 3G/2G in SLOT2 Mar 17, 2017 at 12:57

Dual SIM phones are able to switch between SIM cards LTE support, if your data connection is used by "SIM 2" it will ba able to operate on 2G, 3G and LTE, while "SIM 1" will operate only in 2G and vice versa.

TLDR, SIM used for data connection will operate on 2G,3G and LTE the other SIM card will operate ONLY on 2G.

If your SIM is working on LTE Only mae sure it's the SIM used for data connection otherwise, you will not get network signal on it while your 3G sim card is used for data connection.


SOLVED!!! In my galaxy a7 (2016) running lineage os 17.1 Android 10 ROM

Suddenly one day my data switched from LTE to E And stayed that way for hours So I tried fixing it throw (phone information) (##4363##) But it DID NOT WORK. After a long search online for solutions I came across One that says MANUALLY switching your other Sim that you don't use for internet to 2G then ALSO MANUALLY switching your internet Sim to LTE WILL SOLVE THE ISSUE AND IT DID. Without having to restart the phone, just do it and wait for a couple of minutes and it will flip to LTE

However this should happen automatically, but it might be a bug in the firmware/android If it does not work then may be I'm tripping and my carier fixed it without telling me Bear in mind that in my area there are probably tower maintainance going on or so I've heard so I might also be wrong But definitely try it and if it works don't forget to write back Thanx :D

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