AT&T S9+ G965USQU3ARG7 to Sprint/Boost - Activation Issue - Samsung Galaxy S9+ Questions & Answers

I have a Galaxy S9+ that currently has AT&T firmware G965USQU3ARG7. I registered the phone with Boost, but the hands-free activation will not start, nor do the usual methods work like ##72786#, *#*#72786#*#*, or update PRL (that option is not available on the software). So I was wondering if I could use Odin to flash the latest Sprint firmware to the phone? It looks like the latest Sprint firmware on Sammobile is G965USQU3BRK1, and appears to be a couple months newer than the ARG7 that is on the phone currently. Is this something that I could do, and that would allow me to then activate the phone?
Jordan

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Jordan Keck said:
I have a Galaxy S9+ that currently has AT&T firmware G965USQU3ARG7. I registered the phone with Boost, but the hands-free activation will not start, nor do the usual methods work like ##72786#, *#*#72786#*#*, or update PRL (that option is not available on the software). So I was wondering if I could use Odin to flash the latest Sprint firmware to the phone? It looks like the latest Sprint firmware on Sammobile is G965USQU3BRK1, and appears to be a couple months newer than the ARG7 that is on the phone currently. Is this something that I could do, and that would allow me to then activate the phone?
Jordan
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The latest Sprint firmware should be CSAB, which is pie?
Can you elaborate on hands free activation?
Activation for what?
You should have no problem using Odin to flash whatever firmware you want, but because you're on an MVNO, it'll take some tinkering to get everything working. First, I would check to see whether Boost sells the u version or the u1 and flash according to the phone they sell under their own service.
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Thanks for clarifying the latest version! Its weird b/c Sammobile did not list CSAB for Sprint, but I did see it listed for Verizon. Either way, that should work for my application.
So the "Hands Free Activation" is what Sprint/Boost/Virgin use to program the phone to work with the network. Simply inserting a SIM card like you can do with the GSM carriers is not enough to get the phone working with their network. You have to tell the carrier the IMEI and SIM of the phone, then the phone will go through the "Hands Free Activation" process, then it is ready to use.
Both Sprint and Boost phones use the same firmware, and the specifics to each carrier are handled during the "Hands Free Activation". So I will try out the CSAB firmware later today and report back on if that works!

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The issue you're running into I don't think is necessarily firmware related. The phone is probably carrier locked to Sprint. Has sprint provided you an unlock code to switch carriers?
As far as switching firmware, because you're with an MVNO, personally I would not flash a "U" (carrier specific) firmware unless Boost has carrier specific features you would benefit from using (Which I doubt).
Reason I say that, Sprint uses a different technology/system to provide simultaneous voice and data and using a Sprint (or other U firmware) might cause compatibility issues, in that regard, because you're on an MVNO that can't/may not utilize Sprint's unique system.
That being said, Sprint has (finally) gotten on board with VoLTE which is universal, and has started to implement this into their network.
Most MVNO's have limitations on BYOP (bring your own phone) plans because of the firmware carrier restrictions placed on the phone. For instance, when I switched from Verizon to Straight Talk, I immediately wasn't able to use simultaneous voice/data because I was running Verizon configured firmware through a different carrier.
This was corrected by flashing a universal (Factory Unlocked) G965U1 firmware. This enables the universal VoLTE option the phone has instead of trying to bridge voice/data with Verizon's preset configurations.
Most MVNOs that sell devices with their service, almost unanimously, sell factory unlocked phones that aren't branded to any specific carrier.
Your best option, in my opinion, is to emulate the devices THEY sell (including Boost) by flashing G965U1 firmware (latest package is CSA8). Either download from XDA or Sammobile "XAA Unknown" region for carrier.
That firmware package, when loading it into ODIN you'll have two CSC files. Don't use the CSC_HOME file, use the other one. This will perform a full wipe (backup your data) and change your carrier to "Unknown" and effectively make your phone universal (which boost prefers).
Since Boost has already activated your IMEI on their network, your phone "should" automatically configure itself to their network at the initial setup after the flash.
If you continue to run into any hiccups, let me know and I'll try to help you work through them. Let me know either way how it works out for you. [emoji16]
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---------- Post added at 06:42 PM ---------- Previous post was at 06:37 PM ----------
By the way, flashing U firmware will remove all traces of Sprint from the phone (All the bloatware) and enable free caller ID. Which is a plus of using Unlocked firmware. You can download the boost app through Google play to manage your account after you set up the phone again.
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---------- Post added at 06:42 PM ---------- Previous post was at 06:42 PM ----------
U1 firmware, not U*
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---------- Post added at 06:45 PM ---------- Previous post was at 06:42 PM ----------
I just noticed you said the phone was AT&T branded. As far as I know, AT&T Sim locks their phones and you'll need the unlock code from AT&T to use the phone on another carrier regardless of whether you use ODIN or not. I'm assuming you have this code if you're trying to use the phone dialer to change carriers, correct?
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You are correct that I did get the SIM unlock code for the phone! I also really like the idea of flashing the U1 version of the firmware to the phone! I will get that download started and try that later today, and keep you posted!
Thanks!
Jordan

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You also didn't mention anything about APN (Access point name). This points your device to the appropriate bands and connects to the provided network. You could also try googling Boost's APN settings and changing yours accordingly and seeing if youre then able to connect to their network. Sometimes this must be done manually when not performing a factory reset after switching carriers/sim cards.
Try changing the APN settings and see if you're able to connect. If you can, great!
If you can connect to both voice/data simultaneously, even better.
Then it's just a matter of either leaving the current firmware or switching to unlocked to remove the bloatware and gain free caller ID. [emoji16]
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---------- Post added at 07:25 PM ---------- Previous post was at 07:24 PM ----------
https://bestmvno.com/apn-settings/boost-mobile-apn-settings/
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Its funny that you mention the APN because that was actually the first thing that I tried I found a few different configurations that did not seem to work unfortunately! I am certainly not ruling that out as part of my solution to getting this phone activated though.
The simultaneous voice/data thing is where you sold me! If I can make that work then I would be STOKED!

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Jordan Keck said:
Its funny that you mention the APN because that was actually the first thing that I tried I found a few different configurations that did not seem to work unfortunately! I am certainly not ruling that out as part of my solution to getting this phone activated though.
The simultaneous voice/data thing is where you sold me! If I can make that work then I would be STOKED!
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This post may help with the missing option you were talking about.
https://www.google.com/amp/s/forum....pn-settings-boost-mobile-tested-t3603786/amp/
Sprint is still in it's early stages of VoLTE integration. They were suppose to start implementing it last fall, but that was delayed until December. Most markets are seeing VoLTE already. As long as your APN settings are correct and you're running U1 firmware, you "should" have VoLTE right off the bat. If not, it's a matter of time for VoLTE to pop up on your phone one day soon and have it at your disposal.
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---------- Post added at 07:51 PM ---------- Previous post was at 07:35 PM ----------
Jordan Keck said:
I have a Galaxy S9+ that currently has AT&T firmware G965USQU3ARG7. I registered the phone with Boost, but the hands-free activation will not start, nor do the usual methods work like ##72786#, *#*#72786#*#*, or update PRL (that option is not available on the software). So I was wondering if I could use Odin to flash the latest Sprint firmware to the phone? It looks like the latest Sprint firmware on Sammobile is G965USQU3BRK1, and appears to be a couple months newer than the ARG7 that is on the phone currently. Is this something that I could do, and that would allow me to then activate the phone?
Jordan
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Jordan, try this code and apply the unlock code. #7465625*638*# AT&T does something differently sometimes.
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---------- Post added at 07:57 PM ---------- Previous post was at 07:51 PM ----------
I think you may have been given the wrong dialer code to enter the sim unlock prompt. ?

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hyperblu, thanks so much! I will have access to the phone in a couple of hours and will try that code!

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If that doesn't work, try #7465625*638*#
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---------- Post added at 08:01 PM ---------- Previous post was at 08:00 PM ----------
The 2nd one will probably be the correct one. The code you provided that you claim did nothing is for a Galaxy s6 if I'm not mistaken. [emoji16]
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---------- Post added at 08:15 PM ---------- Previous post was at 08:01 PM ----------
I've never used Sprint or Boost, but I assume you're not using a sim card, correct? You're going from GSM to CDMA and because CDMA doesn't use a sim card...which is the trigger for the sim unlock prompt, that explains why you're not getting a pop-up. The dialer code you tried that did nothing was the likely the wrong code to trigger the prompt too. Let me know. [emoji6]
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---------- Post added at 08:25 PM ---------- Previous post was at 08:15 PM ----------
And just to clarify... Your sim unlock code is a completely separate code from your dialer code to trigger the prompt. I don't want you to mistaken the dialer code as an unlock code. The unlock code will have to be provided from AT&T and you'll have to provide your IMEI to release your phone from their network and they will provide you with an unlock code. If the device is paid in full, you can request an unlock code through their website after providing the IMEI number.
If you have a separate unlock code that you haven't mentioned, good.
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Get it working? Don't leave me hanging!! [emoji23]
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I did get it working!! I used the #7465625*638*# code first to re-enter the unlock, which was successful. After a restart, the phone was still not activating, so I used Odin to install the Sprint version of the firmware (not the U1 because it was not downloaded yet). The phone restarted and immediately recognized the SIM card change and began programming/activating! I now have it working, and am in the process of writing the U1 firmware as I am typing this response!
Thanks so much for your help on this!!
Jordan

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It didn't immediately start programming/activating because a restart alone wont trigger a CSC change. You have to perform a factory reset or completely flash with ODIN for the CSC to switch to another carrier/region whenever you're switching between gsm/CDMA networks. Going from a GSM to a GSM carrier it would've made the switch immediately, with the exception of maybe tinkering with the APN settings.
Switching between gsm and CDMA is a whole different animal and requires a full reset to make the required changes.
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---------- Post added at 05:52 AM ---------- Previous post was at 05:06 AM ----------
Jordan Keck said:
I did get it working!! I used the #7465625*638*# code first to re-enter the unlock, which was successful. After a restart, the phone was still not activating, so I used Odin to install the Sprint version of the firmware (not the U1 because it was not downloaded yet). The phone restarted and immediately recognized the SIM card change and began programming/activating! I now have it working, and am in the process of writing the U1 firmware as I am typing this response!
Thanks so much for your help on this!!
Jordan
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I think you'll like the U1 firmware much better. It won't have the Flipboard and unnecessary/unwanted crap hogging your memory/storage. It's very barebones and unlocks some free goodies too. Glad you got it working though [emoji106] without it, you probably wouldn't be able to get VoLTE with boost. We're you able to make voice/data simultaneously on the sprint firmware?
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ATT phone. I’m on the latest Tmobile Pie firmware. I’m switching to Sprint. What is the best way to switch firmware without “full wipe” and don’t screw up the data/phone? THANKS
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sweetboy02125 said:
ATT phone. I’m on the latest Tmobile Pie firmware. I’m switching to Sprint. What is the best way to switch firmware without “full wipe” and don’t screw up the data/phone? THANKS
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Full wipe has to happen.
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hyperblu said:
Full wipe has to happen.
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Nope. NVM. Put Sprint phone in and it auto configs to Sprint (it auto removed some Tmobile apps and installed bunch of Sprint bloats. Very good. No need to full wipe.
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sweetboy02125 said:
Nope. NVM. Put Sprint phone in and it auto configs to Sprint (it auto removed some Tmobile apps and installed bunch of Sprint bloats. Very good. No need to full wipe.
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Oh wait... You're running 965u firmware. The major carriers will play nice with that. U1 is a different story.
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hyperblu said:
Oh wait... You're running 965u firmware. The major carriers will play nice with that. U1 is a different story.
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Yeah but i just find out the ATT ver missing band 25 and 26 for Sprint. Sprint needs 25, 26, 41 for LTE and ATT ver only has 41. U1 locked phones have everything

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sweetboy02125 said:
Yeah but i just find out the ATT ver missing band 25 and 26 for Sprint. Sprint needs 25, 26, 41 for LTE and ATT ver only has 41. U1 locked phones have everything
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The bands used are determined by firmware. All the carriers , Sprint included, all have capability of running on 26.
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hyperblu said:
The bands used are determined by firmware. All the carriers , Sprint included, all have capability of running on 26.
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Try this *#0011# and tell me if you see 25 and 26. Only 41 there