How to improve mobile Internet on Xiaomi Redmi 9T: from weak signal to maximum speed

Mobile Internet on Xiaomi Redmi 9T often works unstable: pages load for eternity, video in 1080p is constantly “hanging”, then communication disappears in the most unexpected places. The reasons may lie in the settings of the smartphone, the characteristics of the operator or even in the hardware limitations of the model. In this article, we will discuss specific ways to improve the speed and stability of 4G/3G – from basic settings to hidden MIUI features that most users do not know about.

It's important to understand that Redmi 9T (codename lime) is equipped with Qualcomm Snapdragon 662 with X11 LTE modem, which theoretically supports speeds up to 390 Mbps on a 4G+ network. However, in practice, users rarely get even half of this value, because of the wrong network parameters, overloaded operator frequencies or software restrictions. We tested all methods on MIUI 12.5-14 firmware and identified those that give real speed gains of 20-70% depending on the initial conditions.

Before you start setting up, check your current internet speed with services like Speedtest or FAST.com. Write down the results so you can objectively assess the effectiveness of each method. And remember, if the problem lies in the operator's coverage area (for example, you are on the outskirts of town), no setup will replace the physical absence of a tower.

1. Optimize APN settings for maximum speed

Access point parameters (APN) — It's a bridge between your smartphone and your network, and the wrong settings can limit speed or even block access to your phone. LTE. On the Redmi. 9T APN Frequently get lost after updates or changes SIM-map.

To set up the APN correctly:

1. Go to Settings. → SIM-maps and mobile networks → [Yours. SIM] → Access points (APN).
2. Click on the three dots in the top right corner and select the New Access Point.
3. Enter your operator settings (see table below). If your operator is not listed, request the current settings from support.
4. Save the settings and restart the smartphone.

⚠️ Note: If after the change APN The Internet is gone, go back to your settings and select Reset to default. Sometimes operators block manual editing. APN — In this case, request automatic settings through SMS (You usually send a message with the text of the Internet to a short number of the operator).

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If the speed hasn't increased after setting up the APN, try temporarily disabling IPv6 in the AP settings, and some carriers have not optimized their use of the protocol well, leading to delays.

2. Forced 4G Network Selection (LTE)

By default, Redmi 9T automatically switches between 2G, 3G and 4G, which is not always justified. In cities with good 4G coverage, forced mode can significantly improve speed by eliminating jumps between standards.

How to turn on:

1. Open the Settings. → SIM-maps and mobile networks → [Yours. SIM].
2. Select the network type (or preferred network type).
3. Install LTE (or 4G) only.
4. Reboot the phone.

🔹 When it works:

• 📶 In areas with a stable 4G-Coverage (check the operator's coverage card).
• 📱 If the smartphone is often “stuck” on 3G, though 4G available.
• 🔄 With frequent breaks of connection during calls (in mode) 4G VoLTE will be used).

⚠️ Attention: In mode Only LTE If you see a problem with calls, return the settings to the car or on the outskirts of cities. 3G/4G.

3. Enabling VoLTE and VoWiFi for stable communication

VoLTE (LTE voice) and VoWiFi (Wi-Fi voice) not only improve call quality, but also indirectly affect Internet speed. The fact is that without VoLTE when calling, the smartphone switches to 3G or 2G, which dramatically reduces data transfer speeds. On Redmi 9T, these functions are often disabled by default.

How to activate:

1. Go to Settings. → SIM-maps and mobile networks → [Yours. SIM].
2. Turn on VoLTE and VoWiFi switches (could be called Wi-Fi Calls).
3. If you don’t have options, upgrade to the latest version of MIUI or install them via #86583## (Engineering Menu).

🔹 Advantages:

• 📞 Calls do not interrupt the Internet connection.
• 📶 In areas of weak signal, the smartphone will use Wi-Fi for calls.
• 🔋 Battery savings (no constant switching between standards).

⚠️ Attention: On some firmware MIUI After turning on VoLTE, the Internet may disappear. In this case, restart the phone or reset the network settings in Settings → System system → Resetting settings → Resetting Wi-Fi, Mobile Network and Bluetooth.

Make sure that SIM-The card supports VoLTE (ask the operator)|

Update the firmware to MIUI 12.5 or newer|

Enable VoLTE in the settings SIM-map|

Restart your phone after activation |

Check the HD/VoLTE icon in the status bar-->

4. Reset network settings and update firmware

If previous methods failed, the problem may be system failures or outdated software. Network resets remove all stored Wi-Fi networks, passwords and mobile Internet settings, returning them to factory values, often solving problems with “sticking” on slow standards or improper modem operation.

How to reset your settings:

1. Open Settings → System → Resetting settings.
2. Select Reset Wi-Fi, Mobile Network and Bluetooth settings.
3. Confirm the action and restart the phone.

After discharge:

• 🔄 Set up. APN again (see section 1).
• 📶 Turn it on. 4G manually.
• 🔄 Check the speed of the Internet.

If the reset did not help, update the firmware:

1. Go to Settings → About the phone → System update.
2. Click Check Updates and install the latest version of MIUI.
3. For manual installation, download the firmware from the official Xiaomi website and select Install Service Pack.

⚠️ Warning: Before upgrading, check that the battery is more than 50%, and connect to Wi-Fi. If the firmware is “raw” (released less than a week ago), wait for feedback from other users - new versions sometimes contain bugs with a modem.

5.Using an engineering menu to fine-tune the modem

The hidden engineering menu allows you to manually configure modem settings that are not available in the standard interface. It's an advanced method, but it can dramatically improve speed if you know what you're doing.

How to open the engineering menu:

1. Enter the phone code in the app: ##4636##.
2. Select Phone Information (or Phone Information).
3. Scroll down to the Set preferred network type block.

🔹 Recommended settings for Redmi 9T:

• 📶 LTE only - compulsory 4G (analogue of standard settings, but with additional parameters).
• 🔄 LTE/WCDMA Auto – Automatic choice between 4G and 3G (optimal for areas with unstable coating).
• 📡 NR/LTE/WCDMA Auto – if your operator supports you 5G NSA (For example, MTS or MegaFon in large cities).

⚠️ Warning: Do not change other options in the engineering menu unless you understand their meaning! Incorrect settings can lead to complete loss of the network or even overheating of the modem. For example, changing Band Mode settings without knowing your operator’s supported frequencies could make your smartphone “invisible” to towers.

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The engineering menu is a powerful tool, but it's dangerous. If you're not sure about the parameters, limit yourself to preferred network type and leave the other tabs alone.

Verification and replacement SIM-map

It would seem that it could go wrong with SIM-In fact, they're obsolete or damaged. SIM — Older cards (issued before 2018) often do not support modern VoLTE standards or 4G+, Physical defects (such as microcracks) lead to poor contact.

How to check:

• 🔍 Look at this. SIM-A card for scratches, chips or dirt.
• 📅 Check with the operator when your SIM. If she is over 5 years old, replace her with a new one (usually free in the communication salons).
• 📶 Try inserting. SIM If the internet is faster, the problem is Redmi. 9T.

🔹 Signs of “problem» SIM-map:

• 📵 Frequent network loss (signal icon flashes or disappears).
• 🐢 Internet speed drops dramatically after a few minutes of use.
• 📞 Calls are interrupted or the sound is interrupted.
• 🔄 Phone's not catching. 4G, Although other devices in the same location show a stable signal.

⚠️ Attention: On Redmi 9T The hybrid slot is used for the second SIM If you use a microSD, make sure it doesn't interfere with your contacts. SIM-Sometimes it is enough to move the memory card to another slot or use an adapter.

7. Disabling background processes and system optimization

Slow internet is not always the fault of the operator or modem: Background applications, synchronizations and system processes can eat up traffic and processor resources, leaving little power for the normal operation of the network. MIUI This is especially true due to the aggressive optimization of the battery.

How to clean the system:

1. Turn off app autoboot: Go to Settings → Apps → App management → Autoboot and disable autostart for unnecessary programs.
2. Limit background activity: In Settings → Battery and Performance → Battery Management, select Limit background activity for social media, instant messengers, and games.
3. Clear the cache: In Settings → Storage → Cleanup Press Clear Cache (do not delete application data!).
4. Turn off sync: In your Google account settings (Settings → Accounts), temporarily turn off syncing contacts, photos and emails.

🔹 Apps that are “stealing” the Internet:

• 📱 Facebook, Instagram, TikTok – constantly update the feed in the background.
• 📊 Google Play Services – syncs data without you knowing it.
• 🎮 Online gaming (PUBG, Genshin Impact – can download updates in the background.
• 📲 Messengers (WhatsApp, Telegram) – automatically download media files.

⚠️ Warning: Do not disable system processes like com.android.phone or com.qualcomm.qti.telephonyservice, which can cause network loss. MIUI optimizing.

8.Alternative methods: from antenna to custom firmware

If all the standard methods are tried and the Internet is still slowing down, then radical measures remain, which require more effort, but can yield results where conventional settings are powerless.

🔹 Ways for Advanced Users:

• 📡 External antenna: Connection 4G-antennae via adapter MHF4 (It requires disassembling the phone and soldering. Effective in low signal areas, but voids warranty.
• 🔧 Brush firmware: Installing LineageOS or Pixel Experience sometimes solves modem problems, but requires unlocking the bootloader and risks “bricking” the device.
• 📶 Change of change IMEI: In rare cases, it helps if IMEI It's illegal in most countries and it's fraught with legal problems.
• 🔄 Modem replacement: The last step is to replace the modem chip (requires professional repair.

⚠️ Warning: Flashing or modifying your phone can lead to loss of warranty, unstable operation, or even failure.Before any manipulation, back up your data via Settings → System system → Backup.

FAQ: Frequent questions about mobile Internet on Redmi 9T