Root [Verizon] Verizon SCH-I535 on a GSM network...

[jmm92108]

I have spent so many hours researching this and I still can't figure out what the right answer is.
Can the Verizon Galaxy S3 (unlocked) be used on an overseas GSM network by inserting a local SIM card? Its supposed to be an "international" phone, and I read various forum posts where people say the S3 has a GSM radio,and that a recent firmware update enabled the GSM radio. But, I don't see anything about GSM in the S3 specs.

Spec from Verizon web site:
Network: LTE, CDMA/PCS/1xEVDO Rev. A (800/1900 MHz)

I *just* went to a Verizon store to ask this question, and I was told that you can only use the phone internationally on CDMA networks, not GSM. Seems to me that if it is CDMA only then that greatly reduces the usefulness of the phone. And yes I know, people that work at the phone stores don't always give you the correct answers...

So has anybody actually used a GSM SIM card overseas and did it work?

 

[jmm92108]

The guy at the Verizon store said Verizon will not unlock the phone until 6 months after purchase (for new customers). I can't wait that long.
So next question: If I root and flash the phone with a custom ROM, will the phone then be unlocked?

 

[Mikestony]

Well, as far as using the Verizon S3 overseas, I am not sure..as the sim card in our phones are strictly for the 4G LTE, nothing else. But I may be incorrect with the "cannot use overseas" statement

As far as the rooting/flashing custom rom, no, the phone will not be unlocked in the sense of using it for another carrier--that is illegal in the United States without the Carriers permission/action. So Verizon may be correct in what they told you.

After rooting you can unlock your bootloader, but that is different than unlocking for another carrier.

 

[jhawkkw]

The lte slot in the phone will take gsm sims and work if the device is unlocked, and the sim uses a carrier that runs of a frequency that the phone is compatible with. Unfortunately if the sim is locked, it is Verizon's choice of whether to unlock it for you.

 

[Mikestony]

^^^this guy...smart guy

 

[That Afro Guy]

Another thing to look at is frequency band coverage. Most of Europe's 3G network resides on the 2100mHz band. Their 4G frequency spectrum is apples and orange to ours.

 

[jmm92108]

Update on my problem. Today I called Verizon and asked about using my phone overseas. The international tech support person told me the exact opposite of what I was told at the Verizon store. He said that the Galaxy S3 *does* work on GSM networks overseas, if I insert a SIM card, and he said that the phone is unlocked as of right now as long as I have the latest firmware installed.

 

[jmm92108]

Next update to my problem: I went to Mexico and bought a GSM SIM card (IUSACell). I put it in and could not connect to the network. IUSACell is a Mexico telecom and they use 850/1900 GSM. That made me think that the phone was not unlocked or was not GSM compatible.

Then I came back to the USA and tried the Mexico SIM again and this time it connects (roaming). In settings I can force it to search for GSM providers and I can see both AT&T and T-Mobile! So that tells me it does have GSM capability. But when I try to manually select AT&T or T-Mobile, both times it says "Cannot connect to Network". But when I select Global Mode, it does connect to a network but I can't figure out what network it is connecting to. Maybe it is connecting through Verizon, I don't know.
So now I am even more confused and I still don't know how to get my phone to work overseas.

 

[jhawkkw]

Next update to my problem: I went to Mexico and bought a GSM SIM card (IUSACell). I put it in and could not connect to the network. IUSACell is a Mexico telecom and they use 850/1900 GSM. That made me think that the phone was not unlocked or was not GSM compatible.

Then I came back to the USA and tried the Mexico SIM again and this time it connects (roaming). In settings I can force it to search for GSM providers and I can see both AT&T and T-Mobile! So that tells me it does have GSM capability. But when I try to manually select AT&T or T-Mobile, both times it says "Cannot connect to Network". But when I select Global Mode, it does connect to a network but I can't figure out what network it is connecting to. Maybe it is connecting through Verizon, I don't know.
So now I am even more confused and I still don't know how to get my phone to work overseas.

Did it not connect to a network at all, or just not to data?

 

[jmm92108]

Ok, more researching leads me to believe that Verizon totally blocks using AT&T or T-Mobile networks for roaming or any other use. So when I insert my Mexico SIM card in the phone while I'm in the USA, I guess it is roaming on Verizon.

The amount of time I am wasting trying to figure out this phone is not worth it. I am very close to just buying a new phone for international use.

 

[jmm92108]

Did it not connect to a network at all, or just not to data?

Did not connect at all. No signal bars. Could not make a call or SMS.
(BTW I am already aware of the issue that the GS3 can't be used for data because of an APN issue/bug).

 

[jhawkkw]

It must have something to do with those frequency bands. People who go to Europe which uses the 900/1800 bands seem to have no issue with using it.

 

[jmm92108]

That is very odd because the specs from Verizon's website doesn't list either of those frequencies.

Spec from Verizon web site:
Network: LTE, CDMA/PCS/1xEVDO Rev. A (800/1900 MHz)

 

[jhawkkw]

That is very odd because the specs from Verizon's website doesn't list either of those frequencies.

Spec from Verizon web site:
Network: LTE, CDMA/PCS/1xEVDO Rev. A (800/1900 MHz)

Those are the CDMA frequencies, the 900/1800 are GSM frequencies.

Global: GPRS/EDGE/GSM (850/900/1800/1900); HSPA/UMTS (2100)

Also from the Verizon website.

 

[jmm92108]

Global: GPRS/EDGE/GSM (850/900/1800/1900); HSPA/UMTS (2100)

Aha! Now I see it. My browser was only showing me the mobile version of VZN's web site. I changed browsers and now I see the full site with the full specs.

Now it is an even bigger mystery. Why didn't my phone work on the Mexico GSM network...

 

[jhawkkw]

Global: GPRS/EDGE/GSM (850/900/1800/1900); HSPA/UMTS (2100)

Aha! Now I see it. My browser was only showing me the mobile version of VZN's web site. I changed browsers and now I see the full site with the full specs.

Now it is an even bigger mystery. Why didn't my phone work on the Mexico GSM network...

Yeah, that's confusing me as well.

 

[astan]

If you have installed the June 20 update VRBMF1 the Verizon S3 is automatically unlocked for GSM sims. I am in the USA and placed an AT&T sim into my S3 and could make calls using the AT&T sim. Replace the Verizon 4G sim with a GSM sim in the S3, go to Settings, More settings, Mobil Networks. Allow Global Data Roaming Access. Change Network mode to Global. Go to Access Point Names and hit the menu button and press Add new access point. Put in the Access Point information for you GSM sim and you can now make calls and get data access if the sim card and local network will allow it.

You do not need to call Verizon to unlock it. Just make sure you have the latest update VRBMF1 and change your settings.

 

[breadnatty08]

What data speeds are you able to get on AT&T? Only 3G, HSPA+, LTE?

 

[jhawkkw]

What data speeds are you able to get on AT&T? Only 3G, HSPA+, LTE?

I believe only 2g. I think the only hspa frequency it supports is 2100 and at&T is 850.

 

[breadnatty08]

Yeah, I thought VZW would allow GSM roaming, but only overseas and not on a domestic carrier.
Recall when we got to Mexico, got a text from them offering to allow us to roam for some insane amount (this was on a CDMA network locally). Checked an email on the wife's phone since Mexico City airport lacks wifi. Think it cost close to $2 to do that!
BTW, this thread may be useful:
http://androidforums.com/motorola-d...an-do-cmda-4lte-gsm-hspa-image-intensive.html

 

[astan]

If Mexico has CDMA and GSM you might need to change the Preferred network mode from Global to "GSM/UMTS" in Mobile networks if you are trying to use a GSM sim.

 

[quickaudi]

dunno about Mexico and GSM, but I used my S3 (with an AOSP ROM) while in Japan and had full 3G CDMA access (data, phone, etc.) using normal global roaming settings.

 

[jmm92108]

I finally got my phone to work with a foreign SIM card. I bought a Mexico IUSACell SIM card a couple weeks ago and I never could get it to work on multiple trips to Mexico.
So I bought a SIM card form a different carrier called Movistar and it works perfectly. I even have a data connection at ~150kbps. I also tried a friends Telcel SIM and that one works also.
So my mystery is solved: Verizon Galaxy S3 with the latest firmware update is GSM enabled and unlocked for use overseas. But apparently, it works with some GSM providers but not others.

 

[Gringo Greg]

I had exactly the same problem as jmm92108. I got a IUSAcell sim card to work by flashing a Synergy ROM over the stock ROM. I needed to install a separate kernel after to get the camera working. I only have EDGE data speed, but it is better than nothing for using IUSAcell.

 

[jmm92108]

I would love to know why an IUSACell SIM does not work on the stock ROM but it will probably be a mystery forever. I could call Verizon and ask them. Hahaha just kidding, what a waste of time that would be...