Xiaomi Redmi 4X Communication Module: Network Recovery

Owners of the popular budget smartphone Redmi 4X Often face sudden loss of mobile network when the device stops seeing SIM-map or no signal 4G. In most cases, the problem is not a physical antenna failure, but a software failure that affects the modem firmware.

Recovery of the communication module requires careful attention and strict adherence to the algorithm of actions, since incorrect interference with system partitions can lead to complete failure of the device. However, if you follow the proven method, you can successfully bring the phone back to life without going to the service center. In this article, we will discuss in detail the process of updating the modem and diagnosing network settings.

Before you start taking action, you need to make sure that the problem is really software, if after rebooting and retrieving the SIM card, the network status does not change, and the settings menu displays the message "No service" or "SIM-If you don't have a map, then flashing the modem partition is the most effective solution, and ignoring this step can lead to the phone becoming a media player without the ability to call.

Diagnostics of hardware and software

The first step in recovery is to pinpoint the source of the malfunction, and it is a mistake to assume that any communication problems are solved by flashing, because in some cases, the culprit may be an oxidized contact or a damaged plume. Diagnosis begins with a visual examination of the tray and the operator's map for scratches or contaminants.

Then you have to check the device's software logs, and you can track the signal level and the network registration status in the engineering menu, enter the code ##4636## in the dialer to get into the testing section, and this displays information about the network type, signal strength and state of the radio module, and if the fields are filled with zeros or the status of "Disconnected", this indicates a deep communication failure between the processor and the modem.

It is also important to eliminate software conflicts caused by custom Android builds. Users who install informal firmware often forget to update the basic Radio Interface Layer (RIL) files. These files contain instructions for the operating system on how to manage the RF module of a particular model.

⚠️ Warning: If the phone falls or is exposed to moisture, the modem's firmware may not help, and in such cases, there is a high probability of physical damage to the antenna module or the corresponding tracks on the motherboard.

There are several indirect signs indicating the need for interference in firmware:

• 📶 Constant switching between 3G and 2G even in the safe reception zone 4G.
• 🔋 Abnormally fast battery discharge in standby mode associated with constant network search.
• 📵 Complete absence of registration in the network after replacement SIM-card-only.

Only by making sure the software nature of the failure is clear can we move on to tooling, and ignoring the diagnostic phase often leads to a waste of time and unnecessary manipulation of system files.

Tools and drivers preparation

Quality workplace preparation is the key to successful firmware.To work with low-level components Xiaomi Redmi 4X You will need a personal computer running Windows, a good USB-A high-quality shield cable and a stable Internet connection to download files, using damaged cables can cause communication to break at a critical time of data recording.

A key element of training is to install the right drivers, the computer must correctly identify the device in various modes of operation, including bootloader mode and diagnostic mode. HS-USB QDLoader 9008 and standard ADB-Android drivers.

You also need to get superuser rights if you plan to use file replacement methods through the file system. However, the most reliable way is to use specialized software running through Fastboot or other file systems. EDL To do this, download and install the Minimal platform. ADB and Fastboot.

Remember to back up your critical data. While the modem firmware should not theoretically affect the user partition, any manipulation of system partitions carries the risk of losing information.

Search and selection of compatible modem firmware

The most critical step is to find the correct firmware file. The Redmi 4X communication module (codenamed land) is based on the Snapdragon 435 chipset, and the use of files from other models, such as the Redmi 3S or Redmi Note 4X, is strictly prohibited, which can lead to irreversible damage to the IMEI and complete failure of the communication module.

Modem files are usually provided as part of full MIUI firmware. You need to find a firmware archive that matches your current Android and regional version (Global, China, EU). Inside the archive, we are interested in a file with a name containing "NON-HLOS" or simply "modem".

To extract the modem image from full firmware, you can use the ROM Extractor utility or unpack the firmware archive manually by finding the NON-HLOS.bin file. This binary file contains all the necessary calibrations and algorithms for the operation of the RF unit.

When searching for files, look for a release date. More recent versions may contain fixes for specific carriers, but may also have new bugs. The golden rule is: use the modem version that came bundled with the last stable firmware running on your device without any complaints.

Replacement method with TWRP Recovery

If you have a custom TWRP recap on your device, the process of replacing modem files becomes much easier and safer, this method allows you to replace only the necessary partition without affecting the system and user data. First, copy the file modem.img or NON-HLOS.bin to the internal memory of the phone.

Boot into Recovery mode by slamming both the power and volume buttons. In the TWRP menu, go to Install. Here, select the image firmware mode. Press Install Image (usually in the lower right corner) to switch to partition mode.

Select the previously copied modem file. After selecting the file, the system will prompt you to specify the target partition. You must find and select Modem from the list. Be extremely careful: choosing the wrong partition (for example, System or Boot) will cause the phone to stop booting.

⚠️ Note: Before confirming the operation, be sure to back up the current Modem section through the Backup menu in the TWRP. This will allow you to roll back in case the new version is not working.

Once you select a Modem partition, confirm the swipe. The recording process takes a few seconds. Upon completion, press Reboot System. The first run may take longer than usual, as the system will re-initialize the network settings.

Firmware via Fastboot and Command Line

For users who do not have TWRP, or in cases where the Recovery partition is damaged, there is a method of firmware through Fastboot mode. This method requires a connection to a PC and the use of the command line. It is considered more "clean" from a technical point of view, since it eliminates the influence of third-party scripts of the backup.

Transfer the smartphone to Fastboot mode, turning it off and clamping the volume down button when connecting USB-The screen will show a picture of a hare repairing an android. Open the Windows command line (cmd) in the folder where the modem image file is located.

Enter a command to check the connection:

fastboot devices

If the serial number of the device is displayed in response, the connection is set correctly, followed by a command to record the image:

fastboot flash modem NON-HLOS.bin

Here, NON-HLOS.bin is the name of your modem firmware file. Make sure it matches.

After successful execution of the command (it will appear the inscription "finished"), you need to clear the cache of the modem partition to avoid conflicts of old settings.

fastboot erase modem

Then restart the device with the command fastboot reboot.

This method requires accuracy in command writing. A single typo can result in the data being written to the wrong memory address. Always double-check the syntax before pressing Enter.

Network settings and resetting APN settings

Once the communication module is successfully firmwareed, the phone may not work immediately. Often, the old APN settings conflict with the modem's updated software, so the final step is to completely reset the network settings.

Go to the Settings menu → SIM-maps and mobile networks → Access points (APN). From the menu (three dots or the "More" button), select Reset to default.This action will remove all manual operator settings and restore factory settings compatible with the new firmware.

It is also recommended to perform a full network reset if problems persist, and this can be done through the factory reset menu by selecting the option "Erase all data" (pre-backup), which is guaranteed to eliminate any software tails from the old version.

If after all the manipulations the phone sees the network but can't call, check the settings of the preferred network type. Set the LTE/3G/2G (auto). Sometimes forced selection of only 4G (LTE Only) through the engineering menu ##4636## helps stabilize the connection in areas of uncertain reception.

💡

Properly configuring APNs after running a modem is critical to mobile internet, even if voice communication has already recovered.

In some cases, operators require manual input of parameters. MMS This information can be found on the official website of your operator or received by automatic message after installation. SIM-map.

Possible errors and ways to eliminate them

Unforeseen situations can occur during the firmware process, and one of the most common bugs is Error 1 or a message that a signature has failed to verify, which happens if you try to flash a file from another model or region without the bootloader unlocked, in which case you either need to unlock Bootloader officially or look for a firmware signed for your region.

Another problem is the loss of IMEI. If the device status is displayed as zeros instead of a unique number, then the EFS or Persist partition has been damaged. IMEI restoration is a complex procedure that requires a backup of these partitions that prudent users make in advance.

• ❌ Error "Target phone is not responding": Check the cable, port USB Try another port, preferably. USB 2.0.
• ❌ Bootloop: Most likely, the modem file is incompatible with the kernel version of the system.
• ❌ No signal after firmware: Reset network settings and check if the phone is locked by the operator.

⚠️ Attention: If you have lost IMEI And you don't have a backup section. EFS, independent recovery is almost impossible without special equipment (programmers) and paid services.

Understanding the nature of errors allows you to quickly respond and minimize damage. Don't panic if something goes wrong - in most cases, the device can be returned to factory firmware through EDL (Emergency Download Mode) mode.