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

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imax64

Member
Sep 8, 2011
14
2
I am on a Sprint/T-Mobile N20U which was just upgraded to Android 12 and I can still access service mode from the Samsung Phone Dialer, it just requires a different code. That being said, all of the menu options related to unlocking other bands just dump you back to the main menu, making access a bit moot.
which CSC are you using?
 

cyberlion17

Senior Member
Apr 17, 2012
253
62
I am on a Sprint/T-Mobile N20U which was just upgraded to Android 12 and I can still access service mode from the Samsung Phone Dialer, it just requires a different code. That being said, all of the menu options related to unlocking other bands just dump you back to the main menu, making access a bit moot.
Can you share what the code is? I can't access the service mode through the google phone app
 

PedroDaGr8

Senior Member
Aug 1, 2008
103
30
41
San Diego, CA
Can you share what the code is? I can't access the service mode through the google phone app
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.
 
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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.
Try *#2263# It's the Band selection service menu. Choose your active sim (Sim 1 is physical, 2 is eSIM) and then select your bands for your active sim.
 

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Dec 16, 2018
13
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enabling all bands can be done by QPST for Qualcomm devices,
but enabling 5G on Samsung phones for some carrier should be done at GCF configuration which at Android 10 , 11 was accessible by mentioned codes , but on Android 12 still there is no way as i searched , if someone know how we can change GCF configuration on Android 12 , please share.
 

Culex316

Senior Member
Apr 1, 2012
511
219
Miami, FL
Samsung Galaxy S20
I am on a Sprint/T-Mobile N20U which was just upgraded to Android 12 and I can still access service mode from the Samsung Phone Dialer, it just requires a different code. That being said, all of the menu options related to unlocking other bands just dump you back to the main menu, making access a bit moot.
Maybe there's a secret code /procedure to access them because they leave those menus there to make testing easier but they also know that people like us like to poke around in there lol.
 

Culex316

Senior Member
Apr 1, 2012
511
219
Miami, FL
Samsung Galaxy S20
enabling all bands can be done by QPST for Qualcomm devices,
but enabling 5G on Samsung phones for some carrier should be done at GCF configuration which at Android 10 , 11 was accessible by mentioned codes , but on Android 12 still there is no way as i searched , if someone know how we can change GCF configuration on Android 12 , please share.
I just received the Android 12 update for my S20+ and it disabled the hardware CA bands I need for my carrier in Central America. I had originally enabled them using that secret menu code that no longer works, but I can confirm that by using QPST and deleting the "prune_ca_combos" file I got them back.
 

Culex316

Senior Member
Apr 1, 2012
511
219
Miami, FL
Samsung Galaxy S20
how do you connect qpst to samsung phones?

Here is the complete guide I used.

Follow it and you should be able to connect to QPST.

Tip: When you open QPST, you have to add all the ports that appear so that the one that is connected to your phone shows up.

Also, be EXTREMELY, but I mean, EXTREMELY careful with what you modify in EFS file explorer, because one wrong move and you can literally brick your phone/render it a glorified Wi-Fi Tablet.

Just deleting the ca_prune_file like the guide says is OK, I tried it myself and can confirm that all it does is enable all the hardware CA bands, but I cannot stress enough: DO NOT CHANGE ANYTHING ELSE UNLESS YOU ARE 100% SURE YOU KNOW WHAT YOU ARE DOING!
 
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jemfalor

Senior Member

Here is the complete guide I used.

Follow it and you should be able to connect to QPST.

Tip: When you open QPST, you have to add all the ports that appear so that the one that is connected to your phone shows up.

Also, be EXTREMELY, but I mean, EXTREMELY careful with what you modify in EFS file explorer, because one wrong move and you can literally brick your phone/render it a glorified Wi-Fi Tablet.

Just deleting the ca_prune_file like the guide says is OK, I tried it myself and can confirm that all it does is enable all the hardware CA bands, but I cannot stress enough: DO NOT CHANGE ANYTHING ELSE UNLESS YOU ARE 100% SURE YOU KNOW WHAT YOU ARE DOING!
tested working =D.

/nv/item_files/modem/data/3gpp/lteps/disable_apn_matching
/nv/item_files/modem/nr5g/L2/mac/mac_cfg_validate_ctrl
/nv/item_files/modem/nr5g/L2/mac/mac_cfg_validate_ctrl_Subscription0

could the above be related to GCF whitelisting?
 
Last edited:

Culex316

Senior Member
Apr 1, 2012
511
219
Miami, FL
Samsung Galaxy S20
tested working =D.

/nv/item_files/modem/data/3gpp/lteps/disable_apn_matching
/nv/item_files/modem/nr5g/L2/mac/mac_cfg_validate_ctrl
/nv/item_files/modem/nr5g/L2/mac/mac_cfg_validate_ctrl_Subscription0

could the above be related to GCF whitelisting?
I am honestly not sure. What you could do is copy the files to your computer and look at them from there and maybe figure something out, BUT....modify files at your own risk because I am serious when I say that this program can brick your phone.
 

jemfalor

Senior Member
I am honestly not sure. What you could do is copy the files to your computer and look at them from there and maybe figure something out, BUT....modify files at your own risk because I am serious when I say that this program can brick your phone.
i just did a QCN backup using QFIL tool.

*#0808#
RMNET+DM+MODEM+ADPL+QDSS+ADB
launch QFIL
Select port
Backup QCN
 
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Dec 16, 2018
13
2
I think GCF is related to Samsung and it hasn't any thing to do with modem configuration that we can change it by QPST. we should find a way for finding GCF configuration on Android 12.
 

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  • 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.

    10
    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.
    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
    Hey guys, I've just activated aggregation and missing LTE bands on Android 11 for Chinese firmware SM-N9860 (Snapdragon) using QSPT & QXDM tools for Windows. No root needed. Instruction looks big but nothing hard. The only issue it is in Russian for now. If you want to try probably have to use Google Translate. Check my post on 4PDA. I don't know if it will work for your device version or not. Please let me know.
    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