Why do I not have a network mode option on Samsung S5 SM-G900A

[sandorduignan]

I have recently bought a Samsung S5 SM-G900A on ebay and I have had a problem with the mobile data. I have been only able to get the E signal 4g and 4gLte symbol. I live in a rural area and the H+ symbol works much better but I can't get it and there is no network mode option like in my previous Samsungs. I have also tried the *#*#4636#*#* option which is letting me set preferences network but it keeps switching back to LTE/GSM Auto option. It is really annoying. Is there any way I can save the LCD/GSM/CDMA auto into my phone. I am yet to see the H+ sign on my new phone and in my bedroom 4g runs at 2mbps. On my s4 mini I get H+ and it runs at 10mbps. Please Help me

 

[B. Diddy]

Welcome to Android Central! Does it actually give CDMA as an option? The SM-G900A is an AT&T phone, so there shouldn't be a CDMA radio. Are you sure that's the model number?

Certain carriers have been known to lock down some settings, so it's possible that AT&T doesn't allow you to access that in the menu (or Sprint or Verizon, if this is in fact a CDMA phone).

 

[sandorduignan]

Its definitely The SM-G900A and I get the option to change network mode to LTE/GSM/CDMA auto when I press *#*#4636#*#* but I still have the same problem of it reverting back to LTE/GSM auto. I am with the 3 network in Ireland I would really appreciate any help.

 

[ironass]

Its definitely The SM-G900A and I get the option to change network mode to LTE/GSM/CDMA auto when I press *#*#4636#*#* but I still have the same problem of it reverting back to LTE/GSM auto. I am with the 3 network in Ireland I would really appreciate any help.

There is your problem then. The G900A model is a GSM phone that is designed specifically for the U.S. network, AT&T. See, #1.6 of 42 Galaxy S5 models - Dummies Guide. It is only partially compatible, (it does not have a 4G/LTE band Band20-800MHz common on European networks), with the 3 network Ireland which is a GSM network and does not support the old CDMA technology that is only partially used now in the U.S. and China. This is why it is reverting in an attempt to obtain a signal on LTE/4G and GSM. See Will My Phone Work? and CDMA vs. GSM: What's the Difference? and the screenshot...



This model has a mega locked down bootloader and is, on Lollipop and Marshmallow, unrootable and cannot be updated unless you are registered on the AT&T network in the U.S.