I noticed you all are cell network enthusiasts like me, so I figured I’d ask for help.
I have an unlocked Galaxy S20+ (SM-G986U1), U.S. unlocked version, flashed with the latest XAA firmware (and running the XAA CSC).
Lately, my carrier here in Panama (where I live) has deployed NSA 5G on Band 66 (N66) using DSS, which my phone happens to allegedly support, so I go to the Samsung service menu (#27663368378#) to unlock all the bands, NSA/SA 5G , and remove the NR CA prune and all that stuff (according to this guide: How To Guide - How to Enable All Bands Through Service Menu on US/CA S23 series (including Sub-6 and mmWave) | XDA Forums)
Everything is unlocked, but I still cannot connect to the 5G network, even though I inserted my SIM into another 5G phone here and it connected instantly.
I even checked my phone’s UE capability info record (which I uploaded here:
If anyone wants to take a look), and from what I can see, it supports DSS, the N66 band, and MR-DC, meaning it should use my carrier’s LTE bands (B4, B2, B28) as anchors for the 5G.
The UE Capability message also indicates that my carrier requests N66 from my phone, too.
But no dice.
Does the phone need to support a specific NSA 4G anchor band or can it use any one? Or is this something that is CSC-related?
Nope. I do not get a 5G icon and even when I force my Samsung device to look for NR only (by going to the ##4636*#*#), it does not pick up anything, but I do know that it is reporting to the network its 5G capabilities at least.
If you have already tested the SIM card in another 5G phone and it works properly, a potential limitation could be on your own Samsung (for instance if it does not accept 5G registration without SUCI).
Do you know if the identification is just performed through the SUPI?
I am not sure if the identification is performed through SUPI.
I do know that my handset supports at least 3GPP release 16 for 5G.
In any case, I used Wireshark to log the modem’s output (RRC signaling) and did not find anything related to any SUCI or SUPI handshake (see attachment).
I dialed *#0808# on my handset, which opens a USBsettings menu that allows me to expose the handset modem’s diagnostics port via USB, allowing me to log the trace using QCsuper (plus libusb) and Wireshark on Windows.
I then switched the handset from 4G to 5G and viceversa and turned airplane mode on and off as well to capture the UE Capability Information report and see if the handset was even communicating with the 5G network (it logged some NR RRC but not much more than that).
I also noticed that the network requested MRDC bands and the handset confirmed listing the bands in UE-MRDC-Capability.
When I insert a SIM from AT&T or T-Mobile in the U.S., (officially supported carriers), I can see under “UE-MRDC-Capability” that it reports the supported bandEUTRA + bandNR combinations, but with my domestic SIM in Panama, it only reports the bands but no combinations.
I guess an NSA 5G network cannot just “mix-and-match” bands, it requires a supported set of combinations?
