Troubleshooting SIM Card Detection Failures on Rooted Android 15 Devices

We understand the frustration that arises when a critical component of your mobile device ceases to function, particularly after you have invested time and effort into customizing your operating system through rooting. The specific scenario you are encountering—a rooted Samsung Galaxy A07 running Android 15, which previously read SIM cards without issue but now fails to detect them entirely, displaying an “unavailable” status and a persistent “banned” logo—is a complex issue that sits at the intersection of software modifications and carrier restrictions. When a device suddenly refuses to recognize SIM cards, especially after a factory reset performed via a root environment, the problem is rarely simple. It suggests that the issue has become embedded in the firmware or the persistent partition data, rather than being a temporary software glitch.

Our analysis of this situation focuses on the intricate relationship between the rooting process, specifically the use of tools like Magisk, and the security protocols enforced by both the device manufacturer and mobile network carriers. The “banned” logo is a particularly significant symptom; it almost certainly indicates a hardware or software ban triggered by the network’s Equipment Identity Register (EIR) or the device’s internal modem firmware detecting an unauthorized state. This comprehensive guide will walk you through the technical layers of this problem, offering detailed diagnostic steps and robust solutions to restore cellular connectivity to your rooted device.

Understanding the Root Cause: Rooting, Modem Partitions, and Carrier Bans

To effectively resolve the issue where your phone “decides not to read my sim cards,” we must first dissect the potential causes. When you root an Android device, you are fundamentally altering the system partition and gaining privileged access. While this opens a world of customization, it can also create conflicts with the device’s modem firmware, which handles all communication with cellular networks.

The modem (or baseband) operates independently of the main Android OS but interacts with it closely. Certain root methods or modules can inadvertently modify critical system files or flags that the modem relies on to verify the legitimacy of the device and the SIM card. The progression of your symptoms—from a five-hour “banned” state requiring a reboot to an immediate ban—suggests that a flag has been permanently set. This could be a hardware identifier ban, where the carrier has blacklisted your device’s IMEI (International Mobile Equipment Identity) due to detected rooting anomalies, or a software flag within the modem’s Non-Volatile (NV) memory that now rejects all SIM authentication attempts.

The Role of RIL and Modem Firmware

The Radio Interface Layer (RIL) is the software bridge between the Android operating system and the radio hardware. On a rooted device, modifications to the system can corrupt the RIL or the modem firmware. If the modem firmware is outdated or incompatible with the root method used on Android 15, it can lead to a complete failure in SIM detection. The “unavailable” status in your SIM settings is a direct output from the RIL reporting that it cannot communicate with the SIM card hardware.

Furthermore, the “banned” logo points towards a network-level rejection. Carriers maintain a database of devices that violate their terms of service, which often includes using rooted devices on their network if specific security measures (like Samsung Knox) are tripped. On Samsung devices, tripping the Knox warranty void flag (a physical fuse) can trigger software responses that disable secure features, and in some cases, may lead to complications with network authentication if the device’s integrity is checked by carrier apps or the network itself.

Comprehensive Diagnostic Steps for SIM Detection Issues

Before attempting to flash stock firmware or perform more drastic measures, we must establish a baseline diagnosis. A methodical approach ensures we are addressing the correct root cause.

Verify Root Integrity and Module Conflicts

First, open the Magisk app. Ensure that Magisk is properly installed and that the device is still rooted. Check the “Modules” section. A recently updated or newly installed Magisk module is a prime suspect for breaking SIM functionality. Modules that modify the system, such as those for audio, graphics, or network tethering, can sometimes interfere with the RIL. We recommend temporarily disabling all Magisk modules and rebooting the device. To do this, you can use the Magisk app interface or boot into safe mode (if accessible) to bypass module loading. If the SIM card is detected after disabling modules, you can re-enable them one by one to identify the culprit.

Check Modem Firmware Status

Navigate to your device’s dialer and enter the code *#0011# or *#0011# (Samsung Service Mode). This menu provides extensive details about the device’s radio state. Look for any error messages related to the SIM card or network registration. If the Service Mode shows “SIM not detected” or “Modem not initialized,” it confirms a hardware or firmware-level issue rather than an Android OS problem. We also suggest checking the baseband version in Settings > About phone > Software information. If the baseband version is listed as “Unknown” or is blank, the modem partition has been corrupted or erased, which would certainly prevent SIM reading.

Inspect Hardware and Physical Connections

While the issue seems software-related given the history, we cannot ignore the physical aspect. Poor contact between the SIM card and the tray can cause intermittent failures. We advise you to:

1. Power down the device completely.
2. Use a SIM ejector tool to remove the tray.
3. Inspect the SIM card for scratches or corrosion. Clean the gold contacts gently with a soft, lint-free cloth.
4. Inspect the SIM slot inside the phone for bent pins or debris.
5. Test with a different, known-working SIM card from the same carrier. If the new SIM works, the original SIM may be faulty. If neither works, the issue is definitely with the device.

Advanced Solutions: From NV Data Reset to Stock Firmware

If the basic diagnostics do not resolve the “banned” logo and SIM unavailability, we must move to advanced repair procedures. These solutions target the persistent data and the modem firmware directly.

Resetting NV Memory via QPST or QXDM

The Non-Volatile (NV) memory stores critical calibration data for the radio, including network settings and potentially flags related to bans or SIM locks. Corrupt NV items can cause SIM detection failures. To reset the NV memory, you typically need a Windows PC and specialized tools like QPST (Qualcomm Product Support Tools) or QXDM, as the Galaxy A07 uses a Qualcomm chipset. This process requires unlocking the Qualcomm EDL (Emergency Download) mode, which may require a special cable or shorting test points on the device’s motherboard. We use these tools to connect to the phone in EDL mode and read the current NV items. We can then back them up and write a clean set of factory default NV items. This is a highly technical procedure and carries a risk of permanently bricking the device if performed incorrectly. It effectively wipes the modem’s memory, clearing any flags that might be causing the ban.

Flashing Stock Firmware with Odin

Given that you have already performed a factory reset via the root environment and the problem persists, the issue is deeply entrenched. The most reliable solution is to flash the original stock firmware for your specific model number (e.g., SM-A075F) and region using the Odin tool on a Samsung device. This process will overwrite the system, boot, modem, and CSC (Consumer Software Customization) partitions, restoring the device to its factory state.

1. Download Firmware: Locate the exact stock firmware for your Galaxy A07 and Android 15 from a reliable source like SamMobile or SamFw.
2. Prepare Odin: Extract the firmware ZIP file to get .md5 files. Open Odin on your PC.
3. Enter Download Mode: Power off the device. Press and hold Volume Up + Volume Down and connect the phone to the PC via USB.
4. Flash: Load the firmware files into their respective slots in Odin (BL, AP, CP, CSC). Do not use the HOME_CSC file if you want to perform a clean flash that wipes data. Use the standard CSC to wipe the entire device, including user data and potentially persistent ban flags.
5. Start: Click Start and wait for the process to complete. The device will reboot.

This procedure is the most definitive way to fix any corruption in the system or modem firmware. It will remove root, but it should restore SIM functionality if the issue was software or firmware-based. If the device remains banned after a clean flash of stock firmware, the ban is likely a hardware IMEI ban at the carrier level, which requires contacting the carrier to resolve (though they may refuse if they detect rooting). Alternatively, the modem’s NV memory might be locked, requiring the EDL NV reset method mentioned previously.

Preventing Future SIM and Root Issues

Once your device is functional again, if you choose to re-root, we recommend taking precautions to avoid a recurrence.

Use Magisk Modules Wisely

Always verify the compatibility of Magisk modules with your specific Android version and device model before installation. Modules from untrusted sources can wreak havoc on your system. Our platform, the Magisk Module Repository at Magisk Modules, provides a curated list of safe and effective modules. We ensure that the modules available for download are tested and verified to minimize conflicts with critical system components like the RIL.

Keep Modem Firmware Updated

Ensure that your modem firmware (CP partition) is up to date. Samsung updates often include fixes for network connectivity and stability. When flashing firmware via Odin, always use the latest available CP file for your device model.

Conclusion

Resolving a rooted phone that suddenly stops reading SIM cards and displays a “banned” logo requires a systematic approach to identify whether the fault lies in the software, firmware, or hardware. From checking Magisk modules and cleaning physical contacts to performing a deep NV reset or flashing stock firmware, each step isolates the problem further. We have detailed the necessary procedures to restore connectivity, emphasizing the critical nature of the modem firmware and the potential for carrier-level restrictions. By following these guidelines and exercising caution with future root modifications, you can maintain the functionality and stability of your rooted Android 15 device.