[Guide] Service Mode and CSC Guide/Enable LTE/5G Bands and Services/5G Low Band on U1

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Draiter

Senior Member
Aug 10, 2010
58
8
Toronto
All the snapdragon n20 ultra have the same motherboard. In the bottom image you can see the Note 20 ultra motherboard. All model numbers supported. What differentiates the different models is a solder bridge. I'm the top image you see the U 0 D W. The u is bridged in this instance, making it a Sm-n986u. Further, the motherboard type is detected by the bootloader and sets a board id (6,2,0,-;Machine model: Samsung C2Q CHN PROJECT - SM-N9860_REV07C (board-id,10)), that board id is then detected by the modem bootloader and sets the particular config file to be loaded based on the board id (549_a_0.mbn) in the case of the SM-N9860. This config file then sets the particular bands the phone supports. All n20 U support all the bands, they are just encoded by the board and the software. No amount of tweaking that I know of will get around that. You may be able to open the phone and solder a different bridge, but I'm not sure if there are any files put on the phone during the build, that cannot be overwritten.

20220204_192751.jpg 20220204_193209.jpg
 
I happen to have quite a few Note 20 Ultras available for testing, including two that work (BL Unlocked, rooted SM-N9860-CHC and a SM-N986U1-XAA) as well as two that are disassembled (SM-N9860-TGY and SM-N986U1-TMB). If you have any hardware questions or tests you'd like me to run let me know and I should be able to make it happen.

P.S. Draiter is correct about the solder markings differentiating the variants but they are not actually bridging any pads to enable features but rather are just manufacturing markings to label which model phone the board is for. I can also vouch that there is more to bands than just software differences. The US SD models have MMWave antennas that the CHC/TGY/BRI models don't have. And as far as cross flashing CP modem files in odin I can confirm that the phones absolutely throw a fit when attempting to flash "incorrect" CP files. There's apparently a version check that occurs similar to BL files in that you can only upgrade modem versions and I learned the hard way that flashing a lower modem revision CP resulted in a phone that booted but would soon display a popup during setup saying "no IMEI/MEID found" followed by a hard shutoff and bootloop!
 

royhanks3

Senior Member
Dec 29, 2011
506
83
I happen to have quite a few Note 20 Ultras available for testing, including two that work (BL Unlocked, rooted SM-N9860-CHC and a SM-N986U1-XAA) as well as two that are disassembled (SM-N9860-TGY and SM-N986U1-TMB). If you have any hardware questions or tests you'd like me to run let me know and I should be able to make it happen.

P.S. Draiter is correct about the solder markings differentiating the variants but they are not actually bridging any pads to enable features but rather are just manufacturing markings to label which model phone the board is for. I can also vouch that there is more to bands than just software differences. The US SD models have MMWave antennas that the CHC/TGY/BRI models don't have. And as far as cross flashing CP modem files in odin I can confirm that the phones absolutely throw a fit when attempting to flash "incorrect" CP files. There's apparently a version check that occurs similar to BL files in that you can only upgrade modem versions and I learned the hard way that flashing a lower modem revision CP resulted in a phone that booted but would soon display a popup during setup saying "no IMEI/MEID found" followed by a hard shutoff and bootloop!
I am absolutely intrigued and hopeful you'd be able to mess around with these phones to see if you can enable any additional bands with the different solder points
 

Culex316

Senior Member
Apr 1, 2012
511
220
Miami, FL
Samsung Galaxy S20
The code is *#197328640# and you have to use the Samsung Phone app (not the Google Phone App). As I mentioned before, many (if not all) of the menu options that would allow you to enable additional bands just dump you back to the main screen, so it isn't very useful.
I think there is probably a way to access those menus by entering some sort of secret code, because otherwise they would not have left it there in the firmware.
 

Culex316

Senior Member
Apr 1, 2012
511
220
Miami, FL
Samsung Galaxy S20
So, I tried a trick on my carrier-unlocked Galaxy S20+ (originally from Sprint). I downgraded to One UI 3.1 (XAA unlocked version) so I can set all the settings in this hidden menu (enable all LTE bands and remove pruning) and leave them as is so that the changes could hopefully carry over into the Android 12 ROM I flashed.

Didn't work. The very same band prunings occurred as if I had flashed a T-Mobile ROM despite me flashing the unlocked U1 roms and the settings I made in the hidden menu on One UI 3.1 did not carry over into One UI 4.0.

It seems that even on unlocked ROMS there is something in the firmware that checks the original CSC of the phone and sets the "default" band prunings for said CSC, it's frustrating.
 

N1NJATH3ORY

Senior Member
Aug 16, 2010
1,084
188
So, I tried a trick on my carrier-unlocked Galaxy S20+ (originally from Sprint). I downgraded to One UI 3.1 (XAA unlocked version) so I can set all the settings in this hidden menu (enable all LTE bands and remove pruning) and leave them as is so that the changes could hopefully carry over into the Android 12 ROM I flashed.

Didn't work. The very same band prunings occurred as if I had flashed a T-Mobile ROM despite me flashing the unlocked U1 roms and the settings I made in the hidden menu on One UI 3.1 did not carry over into One UI 4.0.

It seems that even on unlocked ROMS there is something in the firmware that checks the original CSC of the phone and sets the "default" band prunings for said CSC, it's frustrating.
How are you updating after you flash it ? I've noticed my Note 20 Ultra it was on one ui 3.0 i made some changes in the service menu to enable all 5G bands then i did a few OTA now i cant select 4G or below as when i select it simply refuses to change it's like 5G is forced on!
 
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Culex316

Senior Member
Apr 1, 2012
511
220
Miami, FL
Samsung Galaxy S20
How are you updating after you flash it ? I've noticed my Note 20 Ultra it was on one ui 3.0 i made some changes in the service menu to enable all 5G bands then i did a few OTA now i cant select 4G or below as when i select it simply refuses to change it's like 5G is forced on!
I download regular OTA updates after flashing the XAA ROM to my Sprint S20+.

Which carrier are you using your S20 on? If it's the U.S. version, I believe some CSCs like Verizon (VZW) or AT&T (ATT) change things in the settings menu and do not allow you to simply switch to 4G only like you can on the T-Mobile (TMB) or unlocked (XAA) CSCs.
 
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N1NJATH3ORY

Senior Member
Aug 16, 2010
1,084
188
I download regular OTA updates after flashing the XAA ROM to my Sprint S20+.

Which carrier are you using your S20 on? If it's the U.S. version, I believe some CSCs like Verizon (VZW) or AT&T (ATT) change things in the settings menu and do not allow you to simply switch to 4G only like you can on the T-Mobile (TMB) or unlocked (XAA) CSCs.

Apologies i'm UK based i imported snapdragon Note 20 ultra unlocked via Malaysia its on TGY firmware i just downloaded older firmware as the April patch has a horrible battery drain as overnight i wouldn't even lose 1% now I'm losing 8 to 10% Joke

if i try to put it on 4G the tab pops up but when i tap it does not change it to 4G I don't mind that but now I'm scared if i flash the older firmware as i can't get into the service menu I'm locked out as on one U.I 3.0 android 11 i had no issues soon as i updated it android 12 service menu via phone dialer does not work!
 

p4t0

New member
Apr 15, 2022
2
3
This worked for me in Android 12 rooted
am broadcast -a com.samsung.android.action.SECRET_CODE -d android_secret_code://27663368378 -n com.sec.android.RilServiceModeApp/.SecKeyStringBroadcastReceiver
 
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alarme134

Member
Mar 18, 2022
28
4
As you can see, mine is selected to VZW/VZW which is the XXX/YYY portion of the XXX/YYY/ZZZ combo (again, ZZZ should not change. Only having root can change this!)
hello, you say at this precise moment that it is possible to change the last CSC (activated id or carrier id) with the root, someone would be how to do it (or rather where the modified files are in the root) ?
thank you in advance
 

kvasimodo

Member
Dec 18, 2018
47
19
Hey. Hey. If I did a downgrade from Android 12 on my S10 5g with Custom ROM to Android 11 Custom ROM , would it then be possible to activate the 5g network via Google dialer by enabling NR band in service mode? Or would it still not work for me? Right now my 5g network at home on my s10 5g doesn't work! But it's strange that in places where there is a 5g network here at home it doesn't work on my phone, but when I come to Germany a neighbouring country the 5g network works normally there 🤷🏻♂️
 

N1NJATH3ORY

Senior Member
Aug 16, 2010
1,084
188
Hey. Hey. If I did a downgrade from Android 12 on my S10 5g with Custom ROM to Android 11 Custom ROM , would it then be possible to activate the 5g network via Google dialer by enabling NR band in service mode? Or would it still not work for me? Right now my 5g network at home on my s10 5g doesn't work! But it's strange that in places where there is a 5g network here at home it doesn't work on my phone, but when I come to Germany a neighbouring country the 5g network works normally there 🤷🏻♂️
You need to check the bootloader on your current O.S then check on Android 11 if the bootloader matches up then you will be able to get access to bands via dailer if not then you will not be able to downgrade as i ran into the same issue on my Note 20 Ultra 5G I'm thinking of rooting it as that's the only way now for me!
 

Romeo Nickolas

Senior Member
Jun 16, 2022
98
26
If someone planning to downgrade just to get the band you want to activate on Samsung Note 20 Ultra 5G US unlocked SM-N986U1

Here's the result:

Before:
Screenshot_20220819-035035_Service mode RIL.jpg

After:
Screenshot_20220723-180435_Service mode RIL.jpg
Screenshot_20220723-180442_Service mode RIL.jpg

It only unlocks band n2 n12 n25 n66 and all available bands in SA.
 
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intheb0x

Senior Member
Dec 8, 2007
1,497
367
Milwaukee WI
OnePlus 8
If anyone wants to know I got the enable guides and UE setting menu back on Android 12.


I am using the stock dialer

I do have a Verizon sim which blocks everything even the star pound 0011 pound code,
After using this method I now have codes back but I cannot access the b a n d menu.
But I can get to it through the menu above but when I try to select performance mode or whatever they call it it says to use the star pound band method but it doesn't work for me cuz it still doesn't work but I can still set everything set up in the guide but I do not have CSC access either...

If anyone wants to try it make sure you have all your drivers installed correctly like you normally would you can probably get all that information up above.

Download this tool I don't know if the link works on this website but this is their official website if they try to make you pay for it just Google it and you'll find it for free but I think it's for free downloadable at this website above.

Now keep in mind I did this with a Verizon sim on a Verizon CSC on a 988u model running the latest Verizon u1 firmware


So I'm not sure if this will work with other cscs or other firmwares but I don't see why not this is why I'm telling everybody so they can hopefully try and it works for them.

After downloading the Sam FW FRP 3.1, on your phone make sure USB debugging is turned on, and make sure on the menu *#0808# it's set to dm+modem+adb.
Then connect your phone, you can either hit info tab right under the word tool at the top to see if it pulls information from your phone if not you have a driver issue but if all is well and information pulls from the phone, continue to the "MTP" menu, there should be an option called "enable secret code for Verizon beta"

Click that and let it do its thing if it comes up with any prompts make sure you follow them and once it finished reboot your phone and try the codes or you can try the codes without rebooting this is the code that works for me.
*#27663368378#*

The menu comes up is the same as above protocol State UE setting etc debug screen RF test hardware test and two more.

Everything seems to work and stick I am still actively trying to have all the band stick but I can confirm when you make changes immediately in the app the band settings you set do take effect but eventually once you leave the app they seem to not stick.

I don't know if this is a rooting issue or a firmware issue but I can confirm I have successfully locked to different LTE bands and I have actively tried to turn on c-band without much luck here because of where I'm located.

But later tonight I'm going downtown where they have sea band and more wideband access and I will be testing this menu I have been trying to get to for the longest time and after I tried the Verizon secret code beta in the app the first code I tried
*#0011#
If that menu works for you immediately after going through the app on your computer with the enable secret code then you're golden and everything should work.

I have successfully removed 5G prune and other settings.

And have noticed that those settings do stick.

Another thing, if anyone needs screenshots I guess I could take some or make a little video of how to do this but it's very simple.

I just got lucky I was originally trying to change my CSC and the app above also works for changing your CSC and I also use Sam key and bought a couple credits to use to change CSC but it was just a waste of money because this app does the same thing for free but let me tell you, when you change CSC through these apps as soon as you're done your phone wants to reboot and it wants to load the settings of your sim card, so basically it makes everything you did worthless because you're right back to a carrier CSC.
Does anyone know any more codes to try to access more menus because it seems like certain codes are working and certain codes aren't.

Be very careful with those menus there's a couple times where I went through certain things and I lost connectivity and I had to go back and change certain settings to get connectivity back you can really mess things up.

The CSC menu is really what I need to get access to, I really need to access the menu so I can turn on that option at the bottom where it doesn't reset your phone every time you enter a Sim because I think on a xaa CSC all 5G bands will be enabled, if you enable them is this true or do they not stick? Also somebody earlier posted some screenshots of the band selection menu that you can get to and they had theirs full of 5G bands where they could toggle them on and off I have tried to reach this person and find out how they had all them 5G bands available in that selection app and he hasn't responded yet I'm really curious about this as well I have heard that the dish firmware has all 5G bands unlocked.

If anyone has any questions please let me know and happy nodding good luck I hope this works for you!
 
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    Hello All,

    Many people have asked about service mode and CSC related questions and I thought we should get a discussion going that is all in one place.

    *DISCLAIMER* I do not take any responsibility for any issues that may occur from changing settings in these screens. They have the potential to cause service or data lost if used incorrectly. You have been warned!

    Service Mode Guide

    Access Service Mode

    To access service mode screen, first download the Google Phone App from the Play Store (Phone by Google-Caller ID & Spam Protection is the official Play Store Name)

    After installing the phone app, open it up and select set as default *Note* You will only need the Google phone app to access service mode-Once all the changes are made you can keep using it or change back to what you were using*

    Another pop-up will show and select the Phone (blue icon) and set as default. Go to the dial pad icon in the bottom right corner and dial the following:

    *#*#27663368378#*#*
    When you dial the last * in the string above, the service mode menu will automatically show. YOU SHOULD NOT HAVE TO HIT THE CALL ICON BUTTON TO MAKE A CALL AT ANY POINT.
    GEtmxR5J-vLwrxtogkVOn01je_6Lch2EYPQxJyU6IiCNwyTJFpjO2A4dRkFo68KPtD0zfV4O4_gAj-QXbWbmLbmsIEeHn8nNRhvEM-v6SJXhS2X1x4lPFZD1-Xsvrf2th1nmMxwaXVBwtJ5n6yOBzlJRGvwIC1ev-Ty0VXTcTyy00OuTUaBzLs-7TJEqNFUh-M117UN9q0Pu3i3csDxjRdNV0fN3zw4eT2WRogZcG3JrrimHnUZEPa9seBdvU9NOarASEZYWEWIMc1-ko9vaXlnNjJUuhPiNnSxXOwPyKK_pLdar0OSzOXgwsaWFPm3sJ-qLZjQc3EP-NDqg_n2qyUCaeamVnPf16_Rxjxwmu1GRSYLOzqwBlg0GjpncgqdeDPXP-Dn2QcHlSgmaATEH_vArZOsdMY8PW8MmbVA4IpwmhFy2pGqb-iNIh6SLlWlHDEpGqrHCZhWMMeF9Nq83-4H6uo3QDAdXuyHkEYB7c7Cu6_DmzsmUUClbq5XgqDzsYrRj23ed6d1pV0_yUvqTCWkWKpqaw2TpJjlafdfbXCrOdKUxSBW-tZ-JLjOgFPpqcRRj11-jgMNy9Rg5NcWJsXV2NGbeMFQQAFa4Rsty2E2q5z1JpQiRXbrzn5lWlGwKAkYBb8IlwRBCEzVmjJIay_VOLDvbYYrGHaqyT5JRssv-SDjPxOqhIYVQA82Z=w373-h800-no
    .

    Congrats, you are now in the service mode menu!

    Enable all LTE and 5G Bands
    *NOTE* Remember whenever navigating through the menus that the android back button on your device will automatically exit you back to the dialer. To go back, you must use the 3 dots menu at the top and select Back.

    To enable all the LTE Bands go to:
    1-Option 2-UE Setting and Info
    2-Option 1-Setting
    3-Option 2-System
    4-Option 9-Next Page
    5-Option 9-Next Page
    6-Option 9-Next Page
    7-Option 9-Next Page
    8-Option 1-Set LTE Band Config
    9-Option 1-Set Default LTE Band

    This should enable all the LTE Bands for the country that the firmware installed is from and the available roaming bands that are set in the firmware.

    For the 5G Bands go back (using the 3 dots in the top) until you see UE setting menu and the 2 options for Protocol and System then:
    1-Option 1-Protocol
    2-Option 9-NR5G
    4-Option 3-NR5G Prune Status
    Here you will see a [1] Remove NR5G PRUNE option as the last line. Select that option. If you visit this menu later, it will show a * next to NR5G PRUNE is Removed and the option will change to [1] Restore NR5G PRUNE, in case you want to go back.

    Enable DSS

    Now that all the bands are enabled, you have to enable the DSS setting. Get back to UE SETTING MENU with Protocol and System options and:
    1-Option 1-Protocol
    2-Option 1-AS
    3-Option 9-Next Page
    4-Option 9-Next Page
    5-Option 2-NR DSS CONTROL
    6-Option 1-NR DSS ENABLE

    Just reboot the phone after this and this should be all that is needed to enable all LTE and 5G Bands and DSS!

    You can then go back into the Google dialer and dial *#*#2263#*#* and this screen will pop:
    g23W28hUIrJQHoFhP371hn1XQCK_w3b9JCOxfOL-bbhSB59PcquenA81d6n-O0HVtLbWbl3jMOgOSacBvtO5bFkpgzjIwMuRpeWntB8tt6xbOajvVxGILaaS_lrhvwlwC6EFC9sBZJsCqKIWTV4ZzEe27mVC6N87ghDJdTI6Ho6SdACNub_PC2Cey1EN8c6wdp96yckcA-C2b7MGZnrplsXHmslJOs0HDU1CO8uxdggQ6xKS5y4SVp0Xz80qsEpVhpakBC173cWSxPsuKS0LUQNgmvVcsA4NakqDSMaeI3luoI_2cpOn52B6k0TCZQOROYdDrT51mb1PXmP3Rk0V1F_lvqn-Yw6t0qrxXHoF1mDjw0fAeFRtQsS2SwbrV5Cbmuc-S5XGbWtiBQ9eTp6c3eXN7y2VtQHTgAcVyd54q0TZXALpPYb9l6vEkqBOejVbuAaGqAQFwRjJY-XEoQss1n_zNcQIVYLq8XSK9s80AlNB8ZG7zXJJk1EdnEcDpe9w--idATqW8AjC8-ZEtevgfvrAdaiZsEgbKSjQ3cQOS9rOsekqG3grAl0jb5jkHTcNw4BoIV4rDG2QYV-2bAH1-tpiwcNXN63izIYcykfMnvMHa9oqr68eN77G96WjMG6U7VcnQMsz26J-55MbHYshBSdkIua8Nk14tqhTyXLc1KmgyNzomCw05REvmmJB=w373-h800-no


    CSC Guide
    CSC (which I think means Carrier Service Code) helps to set what options for settings show in the device for things like voicemail and wifi calling, as well as sets network code information for things like carrier aggregation combos.

    When you go to your phone settings->about phone->software information and look in the Service Provider SW ver. section, you will see as the last line a combo like XXX/YYY/ZZZ. This indicates what carrier sales and network code is set and what brand the phone was manufactured as.

    I think of the XXX/YYY/ZZZ configuration as follows
    XXX=Sales Code-What kind of features are setup in the firmware like wifi calling, video calling and settings menus
    YYY=Network Code-What kind of network features are set for things like carrier aggregation and LTE/5G bands
    ZZZ=Manufactured as Code- What model the phone was originally manufactured as. Ot has no affect on the system settings or options. THIS CAN NOT CHANGE. IT SHOULD ALWAYS BE THE SAME. ONLY A ROOTED PHONE WOULD BE ABLE TO ACCESS THE FILES NECCESSARY TO CHANGE THIS.

    For the Example of VZW/VZW/XAA, this would mean that the phone was sold as unlocked from Samsung and has a VZW SIM in it, setting the sales and network codes to VZW (XXX and YYY should usually be the same since you want the Network setup to match the settings setup in the phone, but they can be different, especially if you try to change the CSC in the U carrier branded firmware.)

    Changing CSC
    *NOTE*Changing the CSC does not necessarily need the Google phone dialer like for the service menu, however, if you are on a CSC where the stock dialer does not provide you with the CSC change screen (Like when your code is XAA/XAA/XAA) you can attempt it through there and see if you can access it. I haven't been able to test this yet, so let me know.

    First, go to settings->about phone and at the top you will see your IMEI. Press and hold on the IMEI number and you will get a popup saying copied to clipboard. Then, go to the phone dialer and dial:
    *#272*
    After you see the numbers dialed at the top, press and hold after the last * and select paste then dial #. Again, you should never have to actually press the call button. A screen will auto pop. If it does not, try the Google dialer.
    Zhs2G-GcSTO6ksWLj_4WmQeqBzyN1NBQPM2whbwJKbygN0WbeqJkR_cTZvCQ_wrHknIDwVrp8MI6vIYVwiVCpnT4xr6R48JXd4UtCe1M5eV67eQDZF7kBoY_smYhUYLocbxuu-WQaePyZJW4nL7VCKNJ0ONjFpgffGNpgK2PCoRpccgSGcJ7BMGuYXBR3YqzjzPGD-p8JzEnYPWcILpFYXBvUopsedGhUQsvmrj_HYGGP9J8C3gc_zU3xLw48aQoAtne2c0vfkQf9tDG2I5UsyA4tU0MAsAdnDEEoIBjthW0W86UQ57mWA17NCxjZU0zOZ1I8_wdbz5YjGwAVWkA7Ungko9BSFOllcKxjvIG9N9lKjFm6zOtEjpdvGNReP7WpL0tL_C3x6Tgc_Qs5VLTGpr7ZKYld5q6_i13XsLI6V9ctUH8d7nDXrvPIuhvBWaerBb6tabxb_OnOli_El3LHcsUq-iVfGDP9zxWEHkft_BDxvG6zkv5BaZAR-g55tAur-HHUuReJ_vLt9nXLO7pNMVLzAkF4FkvjgW2hgqowXCvunCMuGl_90hZlWCGLVnXQH9B7p5eaMfrJwVjDdwXy6whiIukizfW7PDltFxqVF0imAD4eFDNm-HAxOAeVz_b1lmMHOftRL9ze_hHu0eE-v9ea0V0xCqIVPfskOyve7KSt5tKa5UyktPWZGHw=w373-h800-no


    *Pro Tip*
    Since some CSCs do not allow dialing the IMEI (like the XAA CSC) I recommend after you get to this screen to first select the recent menus button on your phone and click on the CSC app icon in the mini view. But beware, this is not working in the One UI 3 beta!!
    WWLUpYTaf2havLIVpFl1sPgVx929cLvK62tGuLVVCBcM0h0cc46EFX_ox5y3EsQsasf4GqsnunYuec_nG9iO3YvxLXeSxBp_n_YnL67Hk6gteXwqBWXD3-xWydtcbOz_jS5YzSnTUhnUGAsRBZzT_QxKZWe3jih3Mqlib7-5LwWLAMSOinOqexDsN_Kl9vwyHP8ZK2JGz9FKp7oAXuenDijy2yfqairzVNApqlsX4JU-kMFoEYHkdNDQvLSHjT1je230mRn5BCCKhN_RAQgbu6_bSgHRY16BfdqudV6GJUrJ5RqRL1g4y_63cxB3x3l55QioPFPGnI16ZhQgxGjLqeHSa1wLMP6p6pCiwX7UoBS9r9ytJp05Wi7_Y2PB7b4vHVWRvxVlftIjwA0KdNTGjS__EErLytBK3WKlC3mI3qUq84LMCT5LIGfZL4NtHJYXgg0MrBAgM5E8rc7-2XIXMQcHw97WXALbu6SF1PGKf2ZdJcRVOrRwZbYCEud9R6iyVSJPLh2HFjjqbLOfBMouN5cJ78FjN9WKJtmOjpMkffKxHUuCID5DQiYz8liSBG1mTnu-fQXQBmld-cxuk2ABqUcf6FKNizuKexyjMA_BlmqTmmCXpJhM7qfLCjxMR0QloD55dxfJX18svhl4J9LiTKHPr6K-kovflgnLT-ws1-hHTwad2pJIqqXvFRgF=w373-h800-no


    Then click on Keep Open for Quick Launching
    XkA07c7Yvt-V5nI-DQmWsNwsYQCJNkpe2QkfoUsWTbKv-x-0CXiX7JCC5zRaX5thnP1Xwz1o2VCmn-PEC1sWu7tdUDox7vXQKAMdjWiR448ESqm8Fy4YUK7awTJWMUTitPMuuv0UM9ZApsHDWoKWT5y4NibjijnosXbwSdqu3LrDWD6bkEFNklk2tKIr4G03JXKtS-rLMz7av79fh-Z5BDJnjDwJr06bRcN9znjUGsjhHI8KU47yljIcRIkY2Y_MxnJHAtG-vvQmPxRQmrRvIJiD7kkHqOA6T7TGb3dRiJZAqPo8BFqjAl_939foy3P6oFrZsdhWueO7M-oh3BUCDis4iao7-IjlUdg2wiQS8vfEtOTeFdlNKrX7njgiv3hhoQNzsP-E8PHJAD-qNiuhgJxq557KtfASYQodGMvUXGqzNLI9pBqw6NZypF0nQYcQRjY4lB_gfREmd4yHreWMJhrMcUe392Tj0sC6AFowhpKMU4hvK9Pc1nihTbYsFd5dVAA_TT4CcXvOIwsXl6W45MuGiESv1uv0sMv26zJz9GfuSlQdO4BZj2mjTgnzsd1IyMTX5yeOMKvwinhEyq4hPsA-Lyu72cCMwfdduCBbck6VV_78eJB_w37MXmC2EwkJClRgx4e32jerCioSzvX20ePR0OrP25aGr_k9I-qMvxaQIPT10ef_4GFhizva=w373-h800-no


    Then you will have a lock at the bottom of that apps recent screen to show it will stay in recent menu, even after reboot and selecting close all apps button
    UfrVLrRCcoUCsZ9ioSBTg0QijNg8zrAqlxHIJ3uZDGQKR6CYNTyofN16j9MChBv_m0lTYd6HYGwVMAkAQcYED0nKC-I6gYivb-prgBlu5qCQn8nJ_Es8i2FtW3uJwE-2ltIiFtfR0Ky1t2Z0dGIcDRGnDfwU-M5VTFwh5rS8n83axjMbDKbNIp89H3RzTuRLzfy7RrlpocLKDCODYLPPGu7kMhUTuYJLExMmWR1LFg16rmfeQfCt4LFUj4uZRo6GncaBIAN8MCJp_hoEAPfLIMElxYzp2GWGZO6fGZF0-qeksu75qTiEJss5YpzFCV0SVsiEAV3f_fR7FiMk6L2p90-dn_mDiO4U8K4lfgP8kFnLeQqLjJoSHxV4wT7VhcHF7IFnxm1QKL8sjHzgcZO_MYGQGWXi5c9TJaFG4HI6tMMMe-IItjz_GR5VQyoTxO4N5kpVAAYqn2E1pRXpD5dBoFqqjGOwXQ8QcprEPZMZJZ8xQB_bwQbTJKjn2DtUIiHY3lroLF3n36E5b14ldHrR07j17qq3PmqYi29YnfTTgm-J_nqPzIf3EDqQoYuGfag4VeZVOiB529Fd-WCGevnq9fGGnpDfqkPh2ueKbE5D45f-PRKcRB2e3dMqKvOQ1J9roK6WndJ35gglPORX94X7C7h931e6eoTRnUDqtDNqbkUutC0Z48S_NnzUAszc=w373-h800-no


    As you can see, mine is selected to VZW/VZW which is the XXX/YYY portion of the XXX/YYY/ZZZ combo (again, ZZZ should not change. Only having root can change this!)

    You can now select a CSC and then click install at the bottom. This will reboot the phone and should not wipe any data.

    *Pro Tip*
    At the bottom of the CSC screen, there is an option that says Don't change carrier(for DEV/QA). Well, you know how when you change the SIM on the U1 firmware, the phone detects and new SIM and reboots to apply the new carrier settings? You can choose this and select install and get a popup showing ENABLED and the phone won't reboot, allowing you to choose the CSC and keep it with whatever SIM is installed.
    SRRgdfXbgVrlX0gi39nrNvCOP5fUpxpsFwx07Uizs4rArx-_Os2b5uiqVeDLnYEQF41bX5NGF4wAWvIt47XdYB5hpIiIgVDqf-Ke7YLX4UhhSDwOjsD8s-jAm1B6uCUw0RS8Fqq1MMH8k9yGZ_EalB5aT1AFCdF1NQjObWcz-is4vo4Cw_PqVdNVvs2zNA70lelgxoBaoLEcqPgATGtWDqj-OyUMInPsXuAEvYrYSgFJmi24zqxTKxbGOPJLyX_xtYBKgcq-EM8fDavpsWdwfAXKG-h9HpaGjeAJU0kBpyvCS_Bpr1BQrS434VWANjlGgK_oXM56Elzv9X9-AMplSVerXoGXZHi95csmxfJS4y1GCBpYv0uOkCc-ptlI9eW7keuRPSlvir0al1RVrAUn8lLQkGKU4nwS3zhoP61qx8cShoLumwqLKX9gJd4RBEb3YhxGu_iaP4MHOAgXlAgQSkNCcRNDDOoIRkd1EbdtHb91oe2IFWBxObET7nhzlksWzEQWyHVdZ06XkKLokjjiTEpzZk3gzDbnRA46HTazxsGe4KvD2s4YSZqZbMUMxhpyB7u2j3WIyJLsYTx5ledUzfLae5r0suTB7uraTAHVRS4n82NfwdvrbvTgeJL_G9f6rSVKKd0h8Srhb8vjbygcvJzzxHn2t2BE_aleUxsmE4NZNI8mQW5FJr00UmQS=w373-h800-no


    Here is a list of the available CSCs on the U1 and the Carriers I have found:
    ACG=NexTech/C-Spire
    ATT=AT&T
    AIO=Cricket
    LRA=Bluegrass Cellular (possibly other smaller carriers also)
    VZW=Verizon
    BST=Boost Mobile
    TMB=Tmobile
    TMK=MetroPCS
    TFN=Tracfone
    USC=U.S. Cellular
    XAA=Unlocked Non-Branded (Google FI is an example)
    XAR=Cellular South
    XAS=Samsung Unbranded Sprint
    CCT=Xfinity Mobile
    CHA=Spectrum (Charter)
    XAG=Some MVNOs that use TMO, like Mint (confirmation needed)
    ATC=Unknown
    FKR=Unknown
    GCF=Global Certification Forum
    WWD=World Wide Device
    SPR=Sprint
    DSH=Dish Network

    I hope everyone finds this guide helpful and I will add/change any information as it is discovered.
    11
    Just check the code on my N9810 BRI
    This method only works on Qualcomm versions
    I use *#*#276633683782#*#* on Google phone dialer
    and it brings up a service mode screen.

    Press [5] RF Test and choose [2] PREF MODE SET
    (or other options also works )
    It will show Please use *#2263# for mode set
    Then just tap three dots on right top menu and choose back
    It will bring you back to the main menu.

    4
    I happen to have quite a few Note 20 Ultras available for testing, including two that work (BL Unlocked, rooted SM-N9860-CHC and a SM-N986U1-XAA) as well as two that are disassembled (SM-N9860-TGY and SM-N986U1-TMB). If you have any hardware questions or tests you'd like me to run let me know and I should be able to make it happen.

    P.S. Draiter is correct about the solder markings differentiating the variants but they are not actually bridging any pads to enable features but rather are just manufacturing markings to label which model phone the board is for. I can also vouch that there is more to bands than just software differences. The US SD models have MMWave antennas that the CHC/TGY/BRI models don't have. And as far as cross flashing CP modem files in odin I can confirm that the phones absolutely throw a fit when attempting to flash "incorrect" CP files. There's apparently a version check that occurs similar to BL files in that you can only upgrade modem versions and I learned the hard way that flashing a lower modem revision CP resulted in a phone that booted but would soon display a popup during setup saying "no IMEI/MEID found" followed by a hard shutoff and bootloop!
    3
    *#*#27663368378#*#* still works for me on TMO N20U (unlocked) after Android 11 update
    but *#272*IMEI# doesn't bring up CSC menu which was available before Android 11 update.
    Following code works to bring up CSC menu.
    Dialed *#*#27262826#*#* on my unlocked Tmobile using google phone app
    3
    Here are some other options in service menu I have changed to improve performance. I have seen it not only help 5G, but LTE as well. I will update the guide soon with full instructions.
    Hi, mellojosh. Great thread. Unfortunately the screen grabs you had in post #25 all disappeared during the forum migration. If there is any way that you can replace them that would be epic. Thanks. 👍