[Samsung Galaxy S22 Ultra] peacey8:
Echoing what @Abaddon said, if the *#73# code doesn't work for you, you can enable the code by switching to VZW CSC first then using SamFW FRP tool to unlock secret codes, then you can switch back to XAA or any other CSC with FRP tool and the code will still work.

So basically, the steps to enable secret codes are:

Start on XAA (or VZW) U1 firmware and enable debugging in Developer menu.

Use SamFW FRP tool to change to VZW CSC if you're on XAA or other CSC. Phone will reboot.

Using SamFW FRP tool, go to MTP -> Enable Secret Code for VZW.

Now you should be able to use *#73# for RF test, or any other secret code (like *#27663368378#* to go directly to service menu).

Switch back to XAA CSC using SamFW FRP tool if needed, and make sure *#73# is still working.

Though, I couldn't get all bands enabled even with having access to this code and following OP's instructions. The bands were still limited to XAA bands, even after pressing Enable twice. However, I was able to enable ALL 5G bands, including mmWave, by using the service menu (credits to this post). You can try these instructions if OP's instructions didn't unlock all bands for you:

Enter the service menu. There's a couple of ways to do this.

Open dialer and enter *#27663368378# to get directly into the service mode main menu.

Open dialer and enter *#73# (OP's code) to get into RF Test mode. Press Band Selection. Press three dots on top right -> Back. Repeat three dots -> back three more times until you get to the service mode main menu.

Use the service mode to set the following options. Note you can go back between screens with three dots -> back for quicker navigation, but I am just starting each option below from the main menu so it's easy to read.

Enable all LTE and 5G bands.

Service Mode Main Menu -> UE SETTING & INFO -> SETTING -> SYSTEM -> Next page 4 times -> SET LTE BAND CONFIG -> SET DEFAULT LTE BAND.

Service Mode Main Menu -> UE SETTING & INFO -> SETTING -> PROTOCOL -> NR5G -> NR5G PRUNE STATUS -> REMOVE NR5G PRUNE.

Service Mode Main Menu -> UE SETTING & INFO -> SETTING -> PROTOCOL -> GCF -> REMOVE ONLY NR WHITELIST.

Optional if you need to enable mmWave bands too: Service Mode Main Menu -> UE SETTING & INFO -> SETTING -> PROTOCOL -> NR5G -> Sub6/mmWave -> ALL ENABLE.

Optional if you have issues going from LTE to LTE+ (carrier aggregation not working properly): Service Mode Main Menu -> UE SETTING & INFO -> SETTING -> PROTOCOL -> AS -> Next Page -> DISABLE CA COMBO CHECK -> DISABLE ON.

Enable 5G NR features (DSS & CDRX) if needed. These options might already be enabled for you by default.

Service Mode Main Menu -> UE SETTING & INFO -> SETTING -> PROTOCOL -> AS -> Next Page -> NR CDRX CONTROL -> NR CDRX ENABLE. NR CDRX is 5G power saving mode.

Service Mode Main Menu -> UE SETTING & INFO -> SETTING -> PROTOCOL -> AS -> Next Page 2 times -> NR DSS CONTROL -> NR DSS ENABLE. NR DSS is 5G Dynamic Spectrum Sharing.

Enable 5G SA if you're lucky enough to live in a country with standalone 5G networks. This option might be enabled by default already.

Service Mode Main Menu -> UE SETTING & INFO -> SETTING -> PROTOCOL -> NR5G -> NR5G SA/NSA Mode Control -> SA/NSA ENABLE.

Service Mode Main Menu -> UE SETTING & INFO -> SETTING -> PROTOCOL -> NR5G -> NR5G SA/NSA Mode Control -> Remove SA permit list.

Service Mode Main Menu -> UE SETTING & INFO -> SETTING -> PROTOCOL -> NR5G -> Next Page -> NR5G NRDC -> NRDC ENABLE. NRDC is for dual connectivity with Sub6 + mmWave bands in parallel. Only applies to 5G SA networks.

Restart your phone, then dial *#73# to get into RF Test Mode. Click Band Selection -> Sim 1 or 2 (whichever you use). On this screen if you scroll down, you'll see a list of enabled NR5G bands like in OP's picture. Make sure all bands are enabled. See my picture below, or OP's picture above (OP's picture is only missing four mmWave bands).

Note that band selection won't be reset with a reboot, but might be reset after a CSC update (or a software update that includes a CSC update). You will have to re-do the settings every update.

This worked for me on XAA firmware to enable 5G in Canada on my S22U. In fact, I was even able to update to One UI 5.0 using the adb sideload method since I was on XAA firmware, and then I repeated the steps above to enable all 5G bands on the beta (secret codes still worked after beta update, but bands got reset after update). So now I have 5G on One UI 5.0 beta in Canada! The trifecta!

Thank you very much @wr3cckl3ss1 for the instructions above, @Abaddon for the key information about VZW firmware needded to unlock secret codes, and @mellojosh for the service menu instructions to change bands.

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