Xiaomi’s Redmi Note 7 series is famous for its popularity, but users sometimes experience critical failures in the radio module. This can manifest itself in the absence of a network, Wi-Fi, Bluetooth or GPS. Often the cause of such malfunctions is damage or loss of the persist partition, which stores unique calibration data for antennas.
Without the correct data in this section, the device becomes a communication "brick" even if the operating system is loading normally. The persist section contains antenna calibration factors unique to each instance of the phone that cannot be recreated manually without a backup. Recovering this memory area requires a specific approach and the use of specialized software.
In this article, we will discuss the process of firmware and repair of a damaged partition in detail. You will work with low-level tools, so the accuracy of each step is crucial for a successful result.
Diagnostics of problems with the radio module and the persist partition
Before you start complex manipulations, you need to make sure that the problem lies in the software failure of the partition, not in the hardware failure. The first sign of damage persist is a complete lack of signal or constant search of the network, even in the presence of a SIM card, and often there is a "gray" IMEI or its complete absence in the system information.
For more advanced diagnostics, you can use the Android Engineering Menu, which is a hidden interface that allows the status of communication modules. Go to the dial menu and type in the code ##4636##. In the menu that opens, select Phone Information.
⚠️ Note: If the engineering menu displays zero values IMEI or "Unknown" status for all networks, the probability of calibration data being damaged is extremely high.
And you also need to check the wireless interfaces, try turning on Wi-Fi and Bluetooth. If the switches go off right away or if I get an error when I turn on, this is a direct indicator of a persist partition problem. In a normal state, these modules should be activated without delay.
- 📡 Complete absence of a cellular network signal in the presence of a SIM card.
- 🆔 Display "Null" or "0" in the field IMEI customized.
- 📶 Inability to turn on Wi-Fi or Bluetooth (slider turns off itself).
- 🌍 GPS Cannot determine the location even in the open air.
Necessary tools and computer preparation
To successfully perform the procedure, you will need a computer running Windows. Virtual machines or MacOS are not recommended due to possible driver problems and connection stability. The main utility for work will be QPST (Qualcomm Product Support Tools).
You also need to install the current drivers for the Qualcomm Snapdragon 660 chipset, which is installed in the Redmi Note 7. Without the right drivers, the computer will not be able to recognize the phone in EDL (Emergency Download Mode) boot mode.
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Use the original. USB-A cable that comes with a kit, or a quality analog with thick wires. Cheap charging cables may not provide stable data transfer, which will lead to firmware errors.
In addition to the software, prepare a file backup of the persist section. The ideal option is a backup made by you personally before the problems occurred. If there is no such copy, you can try to find a file persist.img specifically designed for your model and regional version.
- 💻 PC with Windows (7, 10 or 11).
- 🔌 Correct. USB-cable USB 2.0/3.0.
- 💾 Installed Qualcomm drivers HS-USB QDLoader 9008.
- 📂 Image file persist.img, model.
Installation of drivers and entry into EDL mode
The most critical step is to get your smartphone into emergency boot mode. There are two main ways for the Redmi Note 7. The first is software: through ADB commands. If the phone is switched on and defined by a computer, plug it in and type adb reboot edl into the command line.
The second is hardware, and it's necessary if the phone isn't turning on or being detected in normal mode. You have to remove the back cover of the device. Find Test Points on the motherboard, lock them with tweezers and, without opening, connect them. USB-computer-wire.
⚠️ Warning: When disassembling your smartphone, you risk damaging the plumes or breaking the tightness of the case.Take care, use plastic shoulder blades and warm up the back cover with a hairdryer to soften the adhesive.
After connecting to Windows Device Manager in the Ports section (COM and LPT)" Qualcomm device should appear HS-USB QDLoader 9008. If you are using a “Unknown Device” or"QUSB_BULK", The driver is incorrectly installed or the cable is faulty.
☑️ Connection check
Make sure the correct number is assigned to the system. COM-For the convenience of working in the port QPST It is better to have a low number port (for example, a low number port, COM3 or COM4), Although this is not a strict requirement, you can change the number in the device properties in Task Manager, in the tab "Port Settings" ->"Additionally".
The process of firmware partition persist through QPST
After successfully entering 9008 mode, run the QPST Configuration utility. Go to the Ports tab and make sure your phone is displayed in the list. If the port is visible, then the connection to the processor is established correctly. Next, we will need the QFIL (Qualcomm Flash Image Loader) tool, which is installed along with the main QPST package.
In the window. QFIL Select Flat Build. In the "Select Flat Build" field, click the "Browse" button and specify the path to the file. prog_emmc_firehose_660_ddr.elf (This file is usually bundled with drivers or firmware.
Then click Load XML and select two files: rawprogram0.xml and patch0.xml. However, our goal is to flash through only one specific section. To do this, go to the Tools -> Partition Manager menu.
The path to the firmware file: C:\Users\User\Downloads\persist_recovery\persist.imgIn the section list that opens, find a line called persist. Select it and press Load Image. Select your prepared file persist.img. Once you select the file, the active "Program" button will be activated. Pressing it will start the writing process.
- 📂 Launch QFIL and the choice of Flat Build mode.
- 🔍 Switch to Partition Manager via the Tools menu.
- 📥 Select persist and download image.img.
- ▶️ Starting the Program Button Programming Process.
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If the process is successfully completed, the message "Download Succeed" is marked. If there is a red error message, the process should be repeated by checking the cable and image file.
IMEI Recovery through Engineering Menu
After the firmware partition persist is often required to manually write IMEI, If they're not automatically recovered from the backup, it's an engineering menu. MTK or Qualcomm, but in the case of Redmi Note 7 most often the method works through the application Engineering Mode or special application. APK-file IMEI.
Open the Engineering Mode app and go to Connectivity or Common. Find the CDS Information. Select Radio Information inside. In the input box that opens, you will need to enter the command to install IMEI.
The team has a format AT+EGMR=1,7,"yours_IMEI_1" for the first SIM card and AT+EGMR=1,10,"yours_IMEI_2" Instead of the text in quotation marks, substitute the real one. IMEI, which is indicated on the phone box or on the sticker under the battery (if it is preserved).
| Parameter | Description | Default value |
|---|---|---|
| AT+EGMR | IMEI Recording Team | Only reading. |
| Parameter 1 | Type of operation (1 - recording) | 0 (reading) |
| Parameter 2 | Type IMEI (7 - first, 10 - second) | Not applicable. |
| IMEI | 15-digit device number | Null / 0 |
Once you type in the command, press the "Send AT Command" button. If the operation is successful, you will receive an OK response. Then restart the device. Check network status and IMEI using the code *#06#.
What if the AT team doesn't leave?
Checking results and correcting errors
After restarting the phone, carefully check all communication functions. 1-2 minutes after switching on. The network indicator should display 4G/LTE. Try to make a test call and send it. SMS.
Make sure you check Wi-Fi and Bluetooth. Connect to a wireless network and try to transfer the file over Bluetooth. If everything is stable, then the firmware persist procedure was successful. Otherwise, it may be that the image file was corrupted or did not fit your board revision.
⚠️ Warning: If after all the manipulations the phone starts to heat up in the modem area or quickly discharge in standby mode, immediately turn off the device.
In rare cases, you need a full reset (Wipe Data/Factory Reset) through the Recovery menu to apply changes. To log in to Recovery, turn off your phone and press the power and volume buttons at the same time.
- 📞 Test call to another number.
- 🌐 Checking Internet speed through mobile network.
- 📡 Test GPS navigation.
- 📉 Monitoring of body temperature in standby mode.
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If the IMEI has recovered but the network goes missing after a while, the problem may be in the antenna module or plume, not the software.