Jio 5G Not Working on an Imported Phone: What We Found With a US Galaxy S23 Ultra

By rcert.in Team · 21 October 2026

We use a Samsung Galaxy S23 Ultra that was bought in the United States: model SM-S918U1, the US unlocked version. In India it works fine on Jio 4G, but it has never connected to Jio 5G, even though the phone supports both of Jio's main 5G bands.

This page covers what we tried, what the phone's diagnostic screen actually shows, where an AI chatbot's diagnosis went too far, and what you can do if your imported phone has the same problem.

1. Our Setup

2. What We Tried

We worked through the usual fixes, several of them suggested by an AI chatbot (Google Gemini):

1. Confirmed that the phone supports Jio's 5G bands, n28 and n78.
2. Switched the phone's modem to GCF (Global Certification Forum) test mode through Samsung's hidden service menus. It reported GCF FLAG configured: SUCCESS.
3. Removed the US carrier band restrictions in the same menus, so the phone would scan n28 and n78.
4. Set up Jio's APN (jionet) for IPv4 and IPv6.
5. Swapped in the family member's Jio SIM, which already works on 5G in their Galaxy M33. Still 4G only.
6. Forced the phone into 5G standalone-only mode. It lost service and showed Emergency calls only.

None of it worked. We don't recommend changing hidden modem settings yourself: they didn't help us, and a wrong setting can break calls or mobile data.

3. What the Diagnostic Screen Shows

Samsung's ServiceMode screen (dial *#0011#) showed this while the phone was on Jio:

HPLMN(405-864) sim_state(1)
Serving PLMN(405-864)-LTE
LTE RRC:CONN BAND:5 BW:10
UPPERLAYER_IND_R15 : Not Suppo
DCNR_RESTRICTION : TRUE
NR_BAND: --
NETWORK : UNBLOCK
FINAL IMEI Certi: PASS

Here is what each line means, and what it doesn't:

• LTE RRC:CONN BAND:5: connected to Jio 4G on band 5 (850 MHz). Normal.
• UPPERLAYER_IND_R15 : Not Suppo: this 4G cell isn't advertising a paired 5G cell. Only non-standalone 5G networks, where 4G and 5G work together, advertise one. Jio's 5G is standalone, so this is expected on Jio 4G.
• DCNR_RESTRICTION : TRUE: "DCNR" means dual connectivity with New Radio, that is, using 4G and 5G at the same time (non-standalone 5G). The network has told the phone not to use it. Jio doesn't run that kind of 5G, so this flag is probably shown on Jio 4G for every phone. On its own, it doesn't prove that Jio has blocked our IMEI.
• NR_BAND: --: not connected to any 5G cell.
• NETWORK : UNBLOCK: the phone isn't locked to a US carrier.
• FINAL IMEI Certi: PASS: the phone's IMEI passes the phone's own check. It says nothing about how Jio's network treats it.

The stronger clue is the standalone-only test. When the phone tried to register directly on Jio's standalone 5G, it was refused, while the same SIM registers fine in the M33. So the problem is specific to this phone, not the SIM or the plan.

4. Where the AI Chatbot Went Too Far

We gave Gemini a screenshot of that screen. It concluded that Jio's cell towers were "actively blocking your phone's American IMEI", that the DCNR_RESTRICTION line was the command doing it, and that the block was on Jio's servers rather than the phone. That goes further than the evidence:

• DCNR_RESTRICTION concerns non-standalone 5G, which Jio doesn't use, so it can't be what keeps the phone off Jio's standalone 5G.
• Operators check device IMEIs in their core network, not at the cell towers.
• It ruled out the phone's own software without any evidence. In 2022, Samsung had to release software updates before its Indian phones could use Jio and Airtel 5G, so the software on a US model matters too.

Its practical advice was reasonable: contact Jio and ask them to check the IMEI. Our lesson is that AI chatbots are useful for troubleshooting steps, but a confident diagnosis is worth double-checking before you act on it.

5. So What Is Blocking Jio 5G?

Two explanations fit what we saw, and neither is something a user can fix in the phone's settings:

1. Jio doesn't accept the phone model on 5G. Operators can allow or refuse devices by IMEI, and the first eight digits of an IMEI identify the model. If Jio's standalone 5G only accepts models it has approved, an overseas variant like the SM-S918U1 would be refused, which matches the "Emergency calls only" result. Many owners of US and Canadian Galaxy phones report the same problem in Samsung's community forums.
2. The phone's US software doesn't support Jio's standalone 5G. Samsung enables 5G for each operator in its software: in India, it pushed updates in late 2022 before its phones worked on Jio and Airtel 5G. Owners of overseas models in India report being told by Samsung support that 5G isn't supported on those models here.

Only Jio or Samsung can say which one applies, and it may be both. What we can say is that it isn't the SIM, the plan or the bands.

6. What You Can Do

1. Check that the phone is the problem: put your SIM in a phone that already gets Jio 5G. If it gets 5G there, your SIM and plan are fine. If it doesn't, check your plan in the MyJio app: Jio gives unlimited 5G only on eligible plans or with an add-on.
2. Ask Jio to check your IMEI: use support in the MyJio app, call 199 from your Jio number, or send a direct message to Jio's official X account, @JioCare. Give your phone's model number and IMEI, and mention that the same SIM works on 5G in another phone. Never post your IMEI or mobile number publicly.
3. Escalate if it isn't resolved: register a complaint on 198 and note the complaint (docket) number. If that doesn't resolve it, Jio's website lists an Appellate Authority for each telecom circle.
4. Use Airtel for 5G: Airtel's 5G launched as non-standalone, working alongside its 4G, and owners of US-model Samsung phones widely report that it works.
5. Avoid IMEI or firmware "fixes": changing a phone's IMEI is a criminal offence in India under the Telecommunications Act, 2023, punishable with up to three years in prison, a fine of up to ₹50 lakh, or both. Unofficial firmware can also leave the phone unstable.

7. What Jio and Samsung Could Do Better

• Jio: publish which phone models get 5G, including overseas variants, and tell customers clearly when and why a 5G-capable phone is refused.
• Jio: add a way to request 5G for a device in the MyJio app, instead of leaving it to support escalations.
• Samsung: say clearly whether overseas models support standalone 5G in India, so people know before they buy or bring one.

At the time of writing, our S23 Ultra still connects to Jio only on 4G. We'll update this page if Jio or Samsung fixes it. If your imported phone has the same problem, share this page with others in the same situation.

Information checked against GSMArena's Galaxy S23 Ultra specifications, 3GPP signalling references, Department of Telecommunications notices on IMEI tampering and Samsung Community reports on 21 October 2026. Reliance Jio, Samsung, Galaxy and Airtel are trademarks of their respective owners.