Fixing No Signal on a Samsung Galaxy S5 After a Factory Reset
A Samsung Galaxy S5 can show “No signal”, “Emergency calls only”, or an empty reception icon after a factory reset. The reset usually does not damage the radio hardware, but it can remove mobile network settings, alter the preferred network mode, or expose a problem with the SIM card and carrier account.
For Australian owners in Sydney, Melbourne, Brisbane, or regional areas, the problem may also relate to network compatibility. Older Galaxy S5 models were designed during the 3G and early 4G period, while Australian carriers have since retired 3G services and increasingly require compatible 4G calling.
Start With The Simple Network Checks
Turn Airplane mode on for about 30 seconds, then turn it off. Restart the phone afterwards and check whether the signal bars return. This forces the Galaxy S5 to reconnect to nearby Telstra, Optus, or Vodafone infrastructure instead of relying on the failed connection left from the reset.
Remove the SIM card while the phone is switched off. Inspect it for scratches, clean the gold contacts with a dry, lint-free cloth, and insert it carefully. If possible, test the SIM in another unlocked phone. A prepaid SIM that works elsewhere points towards the handset; a SIM that fails in several phones may need replacement or account activation.
Check the phone outdoors or in a different location. A basement, concrete apartment, underground car park, or rural highway can produce a genuine coverage gap. A handset that reconnects in central Melbourne but not inside a house may have a coverage or antenna issue rather than a software fault.
Restore The Correct Mobile Network Settings
Open Settings > More networks > Mobile networks and select Network operators. Use Search networks and choose your carrier manually if automatic selection fails. Telstra, Optus, and Vodafone may appear under a network name that differs from the retail brand printed on your SIM packaging.
In Mobile networks, set Network mode to an automatic option such as LTE/WCDMA/GSM or 4G/3G/2G, depending on the firmware version. Avoid forcing LTE only while troubleshooting, because an older Galaxy S5 variant may not support every local frequency or voice service required by the network.
A factory reset can also erase the APN profile. The APN mainly controls mobile data, but an incorrect carrier profile can make the device appear disconnected. Use the carrier’s current settings rather than copying values from an unrelated forum post. Sidoharjo’s guide to carrier service settings can help identify the relevant Australian account and data options.
Check Australian Compatibility And VoLTE
The Galaxy S5 was sold in several regional versions, including models intended for different LTE bands. Look at Settings > About device and note the model number, such as SM-G900I, SM-G900F, or another variant. A phone imported from overseas may have weaker coverage in Australia even when the SIM and account are active.
The Australian 3G shutdown changed the situation for older phones. A Galaxy S5 may display 4G data yet fail to make calls if it cannot use VoLTE, or Voice over LTE, with the carrier. Some providers also block devices that cannot make a compliant emergency call over the remaining network. Contact the carrier and ask whether the exact model and IMEI are approved for voice service.
| Symptom | Likely cause | Useful action |
|---|---|---|
| No bars with every SIM | Hardware, IMEI, or incompatible model | Check IMEI and test another location |
| SIM works in another phone | Galaxy network setting or antenna fault | Reset network settings and inspect the SIM tray |
| 4G data works but calls fail | VoLTE or 3G shutdown compatibility | Ask the carrier to verify voice support |
| “Emergency calls only” | Registration, account, or coverage issue | Select the network manually and check the account |
| Signal returns briefly after reboot | Software or unstable radio firmware | Install official updates and test in Safe Mode |
Verify The IMEI And Account Status
Dial *#06# to display the IMEI, or find it under Settings > About device > Status. Compare it with the number printed on the phone’s original box if available. If the IMEI is blank, shows “null”, or differs from the device label, the phone may have a corrupted modem identity and requires professional service.
Ask the carrier to check whether the IMEI is blocked, reported lost, or barred from the Australian network. This is especially important with second-hand phones purchased through online marketplaces. An account can also be suspended because of an unpaid post-paid bill, an expired prepaid recharge, or a SIM that has not been activated correctly.
Do not attempt to change the IMEI. That can be illegal and can permanently prevent network registration. If the handset was imported or previously repaired, retain the purchase record and contact the seller before installing unofficial software.
Repair Software Without Creating New Problems
Install any available official Samsung update over Wi-Fi, then restart the phone. Firmware updates can improve carrier compatibility, but the exact update depends on the model and region. A Galaxy S5 from an Australian retailer should use firmware intended for that model, not a package selected only because its filename looks similar.
If the baseband version is listed as “Unknown” under About device, the modem software may be damaged. A factory reset will not repair that condition. Firmware references such as this repair resource should be treated carefully: verify the model, region, file integrity, and installation instructions before using any package.
Avoid rooting or flashing custom firmware as a first response. An incorrect radio image can remove network functions, trigger security errors, or make warranty and carrier support more difficult. Back up personal files and use Samsung-approved tools or a reputable Australian repair centre when the modem is missing.
Practical Steps Before Seeking Repair
Perform a network settings reset from Settings > Backup and reset if the option is available. This removes saved Wi-Fi, Bluetooth, and mobile network profiles without deleting photos and documents. Re-enter the carrier APN afterwards and test both a phone call and mobile data.
Use these checks in order:
- Test the SIM in another compatible, unlocked phone.
- Test a known-working Australian SIM in the Galaxy S5.
- Confirm the model number, IMEI, and baseband version.
- Ask the carrier about VoLTE, IMEI blocking, and account activation.
- Compare reception outdoors with another phone on the same network.
If the Galaxy S5 fails with several active SIM cards in an area with strong coverage, the antenna contacts, SIM reader, or radio board may be damaged. A repair quote should be compared with the cost of a newer handset that supports current Australian 4G calling and network requirements.
Work through the network, SIM, compatibility, and software checks before buying replacement parts. If the carrier confirms that the phone is unsupported or the IMEI is barred, replacing the handset is usually the fastest route to dependable service in Australia.