Hi all,

I'm using ST's CubeMX implementation on a F4 discovery board. I use ST's USB middlewares with FreeRTOS.

When I get a special OutputReport from PC side I have to answer nearly immediately (in 10-15 ms). Currently I cannot achieve this timing and it seems my high priority tasks can interrupt the USB callback. What do you think, is it possible? Because it's generated code I'm not sure but can I increase the priority of the USB interrupt (if there is any)?

Thank you, David

10 to 15 ms is very slow, so I'm sure its possible.

Where is the USB callback function called from? If it is an interrupt then it cannot be interrupted by high priority RTOS tasks. Any non interrupt code (whether you are using an RTOS or not) can only run if no interrupts are running.

Without knowing the control flow in your application its hard to know what to suggest. How is the OutputReport communicated to you? By an interrupt, a message from another task, or some other way?

The callback which receive the data from PC is called from the OTGFSIRQHandler (it's the part of the HALPCDIRQHandler function). I think the problem is SysTickHandler's priority is higher than OTGFSIRQHandler and it's cannot be modified, but the scheduler shouldn't interrupt the OTGFSIRQHandler with any task handled by the scheduler. Am I wrong that the scheduler can interrupt the OTGFS_IRQHandler?

Poco X4 Pro 5g 128gb Qcn Tested.7z [2021]

The file "poco x4 pro 5g 128gb qcn tested.7z" is a compressed archive containing a Qualcomm Calibration Network (QCN) file specifically for the 128GB variant of the Poco X4 Pro 5G. Core Purpose of the File

The QCN file is a critical system backup containing network-related calibration data for the device's Qualcomm Snapdragon 695 5G chipset. It is primarily used by technicians to:

Fix Network Issues: Resolve "No Service," "Searching," or signal dropping problems.

Repair IMEI: Restore missing or corrupted IMEI/MEID numbers (often caused by improper flashing or hardware repairs).

Restore Baseband: Re-establish cellular connectivity (2G/3G/4G/5G) after a partition wipe or corruption. Technical Breakdown

Target Device: Poco X4 Pro 5G (often referred by its codename "veux" or "peux").

Storage Variant: 128GB (QCN files are often storage-specific to match the partition layout of the internal memory).

Compression Format: .7z (standard 7-Zip compression for smaller file size).

Tested Status: The "tested" label indicates this specific backup has been verified to successfully restore network functionality on a compatible device. Common Use Cases

The file "poco x4 pro 5g 128gb qcn tested.7z" is a compressed archive containing a Qualcomm Calibration Network (QCN) file, specifically used for repairing the network configuration on a Poco X4 Pro 5G with 128GB of storage. What is this file for?

A QCN file contains critical hardware-specific data related to the device’s radio frequency (RF) parameters, including IMEI information, baseband, and network band configurations.

It is typically used by technicians in the following scenarios:

IMEI Repair: Restoring lost or "null" IMEI numbers after a failed firmware flash or software corruption.

Network Fixes: Resolving "No Service" issues or fixing 5G/4G connectivity problems where the hardware is fine but the software parameters are damaged.

Baseband Restoration: Fixing issues where the "Baseband Version" is unknown in the device settings. Review & Technical Warnings

Because this is a specialized repair file rather than a consumer product, "reviews" are generally found in technical repair communities.

"Tested" Status: The "tested" label in the filename suggests a technician has verified it works for the 128GB variant (likely model veux or peux).

Risk of Bricking: Using an incorrect QCN file (e.g., from a different storage variant or region) can permanently damage your device's ability to connect to any cellular network.

IMEI Overwriting: Most shared QCN files have the original donor's IMEI. You must usually edit the file with a HEX editor or use specialized tools (like UMT or QPST) to inject your own original IMEI before flashing.

Security: Always scan .7z files for malware, especially when downloaded from third-party hosting sites or forums like XDA Developers or GSM-focused repair boards. Core Device Context (Poco X4 Pro 5G)

The phone this file supports features a Snapdragon 695 5G processor and a 5000mAh battery with 67W fast charging. While it is a solid daily driver with a high-quality 120Hz AMOLED display, it is noted for having lower gaming performance than its predecessor, the X3 Pro.

Are you trying to fix a specific network issue or IMEI problem on your phone? Provide the details to get more specific technical guidance. Go to product viewer dialog for this item. xiaomi poco x4 pro 6.67" 108MP xiaomi poco x4 pro 5g

The Xiaomi Poco X4 Pro 5G in laser black color is a Dual SIM smartphone with 5G technology, 128GB of storage and 6GB of RAM, 6.67- Go to product viewer dialog for this item. xiaomi poco x4 pro 6.67" 108MP xiaomi poco x4 pro 5g

The Xiaomi Poco X4 Pro 5G in laser black color is a Dual SIM smartphone with 5G technology, 128GB of storage and 6GB of RAM, 6.67- Xiaomi Poco X4 Pro 5G review

It looks like you’re referencing a file named: poco x4 pro 5g 128gb qcn tested.7z

poco x4 pro 5g 128gb qcn tested.7z

Here’s what that likely means:

• Poco X4 Pro 5G (128GB) – That’s the specific device model and storage variant.
• QCN – This usually refers to a Qualifier Calibration Network file (.qcn), which contains IMEI, calibration data, network settings, and other NV items. It’s used with Qualcomm tools (like QPST, QXDM) to restore or repair baseband/IMEI on a device.
• Tested – Suggests the archive contains a QCN backup that the uploader claims is verified to work (at least on their device).
• .7z – A compressed archive (like ZIP, but using 7-Zip).

Important notes:

1. Legal/ethical – Using someone else’s QCN file to change your phone’s IMEI or repair a null IMEI without proper authorization is illegal in many countries and violates mobile network regulations. Only restore your own original QCN backup.

2. What’s inside?
   After extracting (with 7-Zip or similar), you’d likely find:

   • A .qcn file
   • Possibly a .txt or .pdf with restore instructions

3. Risk – Flashing an incorrect QCN can:

   • Mess up your radio (no signal, Wi-Fi, Bluetooth issues)
   • Permanently lose original calibration data
   • Void your warranty

If you originally backed up your own QCN and lost it, and this file is from an identical device (same model, region, hardware revision), it might help as a last resort — but it’s risky.

Recommendation:

• First, try official methods (Mi Flash Tool, factory restore, authorized service center).
• If you proceed, use QPST (Software Download → Restore) and back up your current QCN before writing anything.

Would you like steps to extract/restore a QCN file safely, or to check if this file is safe?

This file is a critical diagnostic and repair tool for technicians and power users dealing with network-related issues on the device. What is a QCN File?

A QCN file contains essential calibration parameters for a device's Qualcomm Snapdragon modem. It is stored in the phone's deepest internal memory (specifically the EFS folder) and holds data such as: IMEI and MEID numbers. Network calibration values for 2G, 3G, 4G, and 5G. Band selection and signal frequency information. Why is this specific file ("tested.7z") used?

The ".7z" extension indicates a compressed archive, and the term "tested" signifies that the data has been verified as working by a technician or the community. It is primarily used in the following scenarios:

IMEI Repair: If a phone's IMEI becomes "Null" or "0" after a software error or a failed flash, this file is used to restore the unique identification numbers.

Network Fixes: If the device loses signal or fails to switch between network generations (e.g., stuck on 3G despite being a 5G phone), the QCN file is re-flashed to recalibrate the modem.

Post-EFS Wipe: During certain advanced repairs, the EFS partition (which holds the QCN data) might be wiped; this file is then used to rebuild the network stack. How the File is Applied

Restoring this file typically requires the device to be in Diagnostic Mode (Diag Mode). Common tools used to interact with this file include:

QFIL (Qualcomm Flash Image Loader): A standard tool for backing up and restoring QCN data.

UMT (Ultimate Multi-Tool): A specialized dongle-based tool often used by professional repair shops.

Hidden Menus: Users can sometimes access a testing menu to check hardware info by dialing *#*#4636#*#*.

Warning: Modifying QCN files is a high-risk procedure. Incorrect use can lead to permanent loss of network connectivity or legal issues regarding IMEI manipulation.

The file "poco x4 pro 5g 128gb qcn tested.7z" is a compressed archive containing a Qualcomm Calibration Network (QCN) file. This critical file stores network-related data, including IMEI numbers, baseband information, and calibration values for 2G, 3G, LTE, and 5G.

A QCN file is typically used to repair network issues such as a "No Service" error, "Invalid IMEI," or failure to switch between network bands. Prerequisites Before you begin, ensure you have the following:

Qualcomm Product Support Tools (QPST): This is the official software required to read and write QCN files. Xiaomi USB Drivers

: Installed on your PC to ensure the phone is recognized in Diagnostic mode. Diagnostic Mode: Enabled on your Poco X4 Pro 5G Go to product viewer dialog for this item. The file " poco x4 pro 5g 128gb qcn tested

to allow the software to communicate with the device's modem.

Unlocked Bootloader & Root (Recommended): Often required to enable Diagnostic mode and write to sensitive partitions. Guide: Restoring the QCN File

Extract the File: Use a tool like 7-Zip to extract the tested.qcn file from the .7z archive. Enable Diagnostic Mode:

Enable Developer Options by tapping "MIUI Version" seven times in Settings > About Phone.

Enable USB Debugging in Additional Settings > Developer Options.

Connect the phone to your PC and use a terminal or specific dialer codes (e.g., *#*#717717#*#* or via ADB: adb shell setprop sys.usb.config diag,adb) to enter Diagnostic mode. The device should appear in Windows Device Manager as Qualcomm HS-USB Android DIAG.

Launch QFIL/QPST: Open the Qualcomm Flash Image Loader (QFIL) or the QPST Configuration tool.

Edit the QCN (If Necessary): QCN files are device-specific. Using a file from another device will copy its IMEI. Use a tool like QCNView or a Hex Editor to replace the dummy or original IMEIs in the file with your device's actual IMEIs (found on the box or by dialing *#06#). Restore the File: In QFIL, go to Tools > QCN Backup Restore. Select your edited .qcn file in the "Restore" section. Click Restore QCN and wait for the "Succeed" message.

Reboot: Once finished, restart your device. Network functionality should be restored. Important Warning

Altering or repairing IMEI numbers is subject to local laws and may be illegal in some regions. This guide is for educational purposes or for repairing a device with its original, legal IMEI.

Are you experiencing a specific network error or null IMEI that led you to this file?

The file "poco x4 pro 5g 128gb qcn tested.7z" is a compressed archive containing a Qualcomm Calibration Network (QCN) backup specifically for the 128GB variant of the POCO X4 Pro 5G Go to product viewer dialog for this item. (code-named "veux").  File Purpose 

A QCN file is a critical system file found in Qualcomm-based devices that stores network calibration data. It is primarily used for: 

Network Repair: Fixing issues where the phone has no signal, cannot switch between 2G/3G/LTE/5G, or shows a "Baseband Unknown" error.

IMEI Restoration: Restoring the IMEI and MEID numbers if they have been corrupted or lost during a firmware flash or "System has been destroyed" error.

Post-Repair Calibration: Ensuring the modem functions correctly after a hardware repair or motherboard replacement.  Technical Details  Device: POCO X4 Pro 5G (Xiaomi). Storage Variant: 128GB. Processor: Qualcomm Snapdragon 695.

Archive Format: .7z (Requires a tool like 7-Zip or WinRAR to extract).

"Tested" Status: Indicates the file has been verified by a technician to work for restoring network functionality without errors.  How to Use This File 

Restoring a QCN file typically requires specialized software like the Qualcomm Flash Image Loader (QFIL) or professional GSM repair tools (e.g., UMT, UnlockTool, or QPST). 

Important Note: Restoring QCN files often requires the device to be in Diag Mode (Diagnostics Mode) and may involve a "QCN Edit" step to input your device's original IMEI numbers to avoid legal or network blacklisting issues. 

QCN (Qualcomm Calibration Network) file for the Poco X4 Pro 5G (128GB) Go to product viewer dialog for this item.

is a critical system file used to restore or repair the device's network-related functions. These files are typically compressed in formats like for sharing in technical communities. Core Purpose Network Repair

: Fixes issues where the phone cannot connect to 2G, 3G, 4G, or 5G networks or fails to switch between them. EFS Restoration

: It contains essential calibration data and identifiers like Poco X4 Pro 5G (128GB) – That’s the

numbers. If these are lost due to a bad firmware flash or software error (e.g., "NV Data Corrupted"), a tested QCN file can restore them. Baseband Fix

: Used when the phone shows "Unknown Baseband" in the system settings, which usually results in "No Service". Key Specifications for This Device Poco X4 Pro 5G (code name:

) requires a specific QCN file compatible with its hardware: : Snapdragon 695 5G. Storage Variant

: While 128GB is specified, the QCN data primarily matches the processor and modem configuration rather than storage capacity. Network Compatibility

: Includes calibration for Sub6G 5G bands (n1, n3, n5, etc.) and various FDD/TDD-LTE bands. POCO Global Common Tools for Flashing file, the device usually needs to be in Diagnostic Mode . The following tools are commonly used for restoration: QFIL (Qualcomm Flash Image Loader)

: The standard official tool for Qualcomm devices to backup and restore QCN files. UMT (Ultimate Multi Tool)

: A professional technician tool (QcFire module) for advanced network repairs. Hex Editors

: Often used by technicians to edit the dummy IMEI in a shared QCN file to match the phone's original IMEI before flashing. POCO X4 Pro 5G | POCO Global

The keyword "poco x4 pro 5g 128gb qcn tested.7z" refers to a compressed archive containing a Qualcomm Calibration Network (QCN) file specifically configured for the Poco X4 Pro 5G (128GB variant). This file is a critical component used by technicians and advanced users to repair network-related issues, such as invalid IMEI numbers, baseband errors, or lack of 5G/4G connectivity. What is a QCN File?

A QCN file serves as the "identity" and "calibration" map for devices using Qualcomm Snapdragon processors.

Network Settings: It stores essential data for frequency bands (2G, 3G, 4G, and 5G).

IMEI & MEID: It contains the unique identifiers for your device. If these are lost (showing "IMEI Null"), the phone cannot register on any network.

Calibration Values: It ensures the radio hardware is tuned correctly to transmit and receive signals effectively. Why You Need the "Tested" 7z File

The ".7z" extension indicates a highly compressed archive. The term "tested" is vital in the mobile repair community because using an incorrect or corrupt QCN file can permanently damage the device's radio frequency (RF) hardware or lead to a "No Service" error. A tested file from a reputable source like Xiaomi Tools confirms that the data has been verified to work on the specific Poco X4 Pro 5G hardware (often codenamed veux). Common Issues Solved by This File

IMEI Repair: Restores original IMEI numbers after a failed flash or accidental "Wipe EFS".

Baseband Unknown: Fixes software-level corruption that causes the phone to lose its modem information.

Network Switching: Solves problems where the phone stays stuck on 2G and won't switch to 5G. How to Use the QCN File for Repair

Repairing the Poco X4 Pro 5G generally requires specialized software and hardware interfaces: All Xiaomi Phone QCN Backup Files

1. Introduction

The filename "poco x4 pro 5g 128gb qcn tested.7z" implies a packaged dataset or toolset relevant to a Xiaomi Poco X4 Pro 5G smartphone (128 GB variant). The suffix ".7z" indicates the 7‑Zip archive format. "QCN" typically refers to Qualcomm Calibration Network (QCN) files—binary files storing IMEI-related calibration and modem configuration data. "Tested" suggests the archive's contents were validated by its creator.

Purpose of this paper: provide a clear, actionable overview for technically inclined readers about what such a file likely contains, intended uses, verification and safety checks, and legal/ethical considerations.

2. Technical Background

• 7z archive

  • Compressed container supporting multiple files, encryption, and checksums.
  • Commonly used to bundle firmware, backups, or tools.

• Poco X4 Pro 5G (context)

  • A Qualcomm‑based Android smartphone; models may use Qualcomm SoCs and modems.
  • Firmware, calibration, and network configuration files are vendor/SoC specific.

• QCN files

  • Contain NV (non‑volatile) items for Qualcomm modem configuration: IMEI, RF calibration, PRL, and other network parameters.
  • Created/used by Qualcomm tools (e.g., QPST, QFIL, QCN backup utilities) and some third‑party utilities.
  • Restoring an incorrect QCN can brick radio functions, cause IMEI loss/mismatch, or violate carrier/authentication rules.

Error: "QCN File is Corrupted"

• Re-extract the .7z file. Ensure you have the latest 7-Zip version.
• Redownload the file – it may have been truncated.

Thank you for the answer, I think I'm a bit confused with the Cortex ISR priorities :-) What I can observe is if I use a much higher osDelay in my high priority task I can respond for the received USB message much faster. This is why I think tasks can mess up with my OTG interrupt.