Modern Xiaomi, Redmi and POCO smartphones have powerful modems that can support a wide range of frequencies and communication standards. However, the standard MIUI or HyperOS interface often hides settings that allow you to force the device to switch to a specific mode of operation, this is especially true in areas with unstable coverage, where the phone constantly “jumps” between 3G and 4G, draining the battery and losing data packets.
The engineering menu is a hidden part of the system, designed for hardware testing and deep diagnostics, and this is where the Phone Info (or similar) tool allows you to control the preferences of the radio module, which, unlike conventional settings, gives you direct access to the modem commands, bypassing the software limitations of the operator or firmware.
Before making any changes, it is important to understand the risks. Incorrect configuration can lead to temporary loss of signal or inability to make calls. Changing the type of network in the engineering menu does not increase the physical power of the antenna, but only changes the priority of connecting to cell towers. In this guide, we will discuss in detail the process of entering, configuring and returning to factory parameters.
What is an engineering menu and why change the type of network
The Engineering Mode is a diagnostic interface built into the software of a smartphone based on MediaTek or Qualcomm processors. For Xiaomi users, it is often the only way to lock a phone in LTE Only or NR Only (for 5G) mode, if the standard menu does not provide such an option.
The main reason owners resort to this procedure is the unstable operation of the mobile Internet, where a device spontaneously switches to EDGE or 3G in the zone of confident 4G reception, is solved by a forced choice of a standard, which is also useful for gamers who are critically important to low ping, or for users in roaming, where automatic network selection is not correct.
However, it is worth remembering that the forced activation of LTE only mode can make it impossible to incoming and outgoing voice calls if your carrier or tariff plan does not support VoLTE (Voice over LTE) technology, in which case the phone simply will not be able to route voice traffic through the data network.
⚠️ Warning: Changing the radio module settings in the engineering menu may cause the signal to temporarily disappear. If the connection does not appear after the changes, reboot the device or reset the network settings.
How to enter the hidden diagnostic menu
The hidden features on Xiaomi smartphones are accessed through a special dialog box called by the codes in the Phone app. The most versatile and working on most models (Redmi Note, Mi, POCO) is the code ##4636#. After entering the last characters, the menu should open automatically without pressing the call button.
If the standard code doesn't work, it's possible that your firmware version or regional modification is blocking that access. In such cases, you can try alternative combinations, although they are less effective on modern shells. There are special applications from Google Play, such as Force LTE Only (4G/5G), which are essentially shortcuts to call the same hidden menu.
Owners of MediaTek-based devices sometimes use the #3646633## code, but on Xiaomi’s global versions it is often replaced with the standard Android code listed above. If none of the codes respond, check if the code set feature in the security settings or the caller app is disabled.
Step-by-step instruction: selecting network mode
Once you've successfully entered the code, you'll see a list of test menus, and we're interested in Phone Information, and if you have two SIMs, you'll be asked to choose SIM 1 or SIM 2, and you'll want to choose which one you want to use for mobile Internet.
In the window that opens, scroll down to Set Preferred Network Type, where the drop-down list with the current mode is usually LTE/TD-SCDMA/WCDMA or a similar combination option that allows the phone to choose the standard itself.
To force 4G, click on the list and select the option that says LTE Only. Some fifth-generation devices may have NR Only or NR/LTE options available. Once selected, the network may briefly disappear and reappear with a 4G or LTE icon.
☑️ Checking network settings
Importantly, once the smartphone is rebooted, the settings in this menu can be reset to standard, which is normal Android security behavior, in which case you will have to repeat or use third-party fixing apps that automatically restore the desired mode when you start.
Table of decoding of network modes
In the drop-down list of engineering menus, you can find many abbreviations, the meaning of which is not always obvious, and understanding the difference between them will help you choose the best option for your situation and avoid problems with coverage.
| Regime. | Description of the standard | Recommendation |
|---|---|---|
| LTE Only | Only 4G network. | For a stable Internet, if you have VoLTE |
| WCDMA Only | 3G only (UMTS) | For voice calls in the bad 4G zone |
| GSM Only | 2G only (EDGE/GPRS) | Only for emergency or saving charge |
| LTE/TD-SCDMA/WCDMA | Auto-mode (4G/3G/2G) | Standard mode for everyday use |
| NR Only | Only 5G. | 5G coverage testing (requires support) |
Choosing GSM Only mode can be useful in situations where battery life is as long as possible, and the Internet is not required at all. 2G catches much further and better breaks through walls than the high-frequency networks of the new generation.
Why do settings reset after rebooting?
Problems with voice calls in LTE Only mode
The most common problem after switching to LTE Only is the inability to make a call, which is because classic voice communication works over 2G and 3G networks (Circuit Switching technologies), and LTE was originally created only for data transfer (Packet Switching).
The phone is in the “only” mode. 4G» You need to support VoLTE (Voice over) technology. LTE). Your operator must support this function, it must be activated on your SIM-map, and also included in the settings of the smartphone (Settings) → SIM-maps and mobile networks → Use VoLTE).
If VoLTE is not working or is not supported, you will have to manually switch back to mixed mode (LTE/WCDMA/GSM) before an important conversation. Otherwise, the subscriber will hear the beeps, but the connection will not occur, or you will see a call error message.
⚠️ Attention: In mode LTE Only without VoLTE enabled you may not get SMS-confirmation code from a bank or service, as some gateways deliver messages through channels 2G/3G.
Using third-party applications to fix the network
As the engineering menu is reset after the reboot, many Xiaomi users resort to the help of specialized software. Force LTE Only (4G/5G) is available on Google Play and allows you to quickly apply the desired network profile with a single click.
The principle of operation of these utilities is simple: they do not change system files, but simply automatically enter a network switch command every time you open an application or when you start the system. This bypasses the restriction on resetting, since the command is executed after the OS is booted.
When using third-party software, be careful about the permissions you request. The app needs access to your phone and network status, but it shouldn't require access to contacts or a gallery. Always check developer ratings and reviews before installing.
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Before installing third-party applications for network management, take a screenshot of the current settings in the engineering menu, which will help you quickly return everything as it was if the program is not working correctly.
How to return standard network settings
If network experiments have caused a signal to disappear completely or the device to function in an unstable way, the settings must be returned to the original state. The easiest way is to re-enter the engineering menu with code ##4636## and select LTE/TD-SCDMA/WCDMA (or Auto).
If the menu doesn’t open or the settings don’t apply, a full network reset will help. Go to Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth. This operation will remove the stored Wi-Fi and Bluetooth pairing passwords, but return the radio module to factory settings.
As mentioned earlier, when Android starts, it often initializes the modem with the secure default settings, which can solve the problem of a dead network.
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Return to Automatic Network Selection (Auto) is the most reliable solution for everyday use, providing a balance between Internet speed and voice availability.