How to speed up mobile Internet on Xiaomi Redmi 9: from simple tricks to hidden MIUI settings

Your Xiaomi Redmi 9 is slowing down on the Internet, although the operator promises high speeds? The problem is familiar to many owners of this budget smartphone. Even with support for 4G LTE Cat.12 (up to 600 Mbps), the real speed often sags to 10-30 Mbps – 5-10 times lower than stated, not only because of overloaded towers, but also the hardware limitations of the Helio G80 processor when processing batch data, as well as the “suffocated” settings of MIUI by default.

12 proven ways to speed up mobile internet on Redmi 9, including little-known Engineer Mode tricks, optimization DNS and even hardware chips (for example, why the second one is not so important) SIM-The first card can steal the speed of the first. MIUI 12-14 and do not require root permissions unless otherwise stated, let’s start with the simplest and get to the advanced settings that Xiaomi hides from users.

1. Checking the basic parameters: what is stopping your Internet?

Before digging into the settings, make sure the problem isn't with external factors. Here are 4 key points to check:

  • 📶 Signal Level: If the indicator shows 1-2 division, smartphoneforced at a reduced speed (for example, with a 4G on 3G). Use the NetMonster or CellMapper app to see the real level RSRP (optimally: higher -100 dB).
  • 🔄 Tower overload: Rush hour (18:00–23:00) speed may fall 40-60%. Check the speed on another device (for example, on a friend’s phone with the same operator).
  • 📱 Energy Saving Mode: Do you have a Battery on? → Power saving mode? It restricts background data transfer, which reduces the download speed on the computer. 20-30%.
  • 🔗 Connection type: Go to Settings → SIM-maps and mobile networks → Type of network. If it costs "Only" 3G" or "Auto (3G/2G)", switch over "4G (recommended)".

Pay special attention to the second SIM-The Redmi 9 (like most budget Xiaomi) uses one antenna on both. SIM. This means that if the second SIM It's active, it can steal up to 30 percent of the speed of the first one. SIM Or take it out if you don’t use it.

📊 What kind of operator are you on Redmi 9?
MTS
Beeline
MegaFon
Tele2.
Yota
Other

2. Optimization of MIUI settings: hidden speed parameters

MIUI by default limits some networking features to save battery life, and these settings can be changed without root rights.

The first thing you need to do is turn off Smart Network Switch, which automatically switches your smartphone from 4G to 3G/2G at low signal, but often does it too aggressively.

Settings → SIM- Maps and Mobile Networks → [Select SIM] → Smart Network Switching → Turn off

The second is to enable VoLTE and VoWiFi (if the operator supports it), which not only improves the quality of calls, but also optimizes data transfer.

Settings → SIM- Maps and Mobile Networks → [Select SIM] → Enable VoLTE and VoWiFi

The third is to change the network type to "Only 4G" (even if you have an "Auto"), which will prevent the smartphone from switching to 3G, where the speed is 5-10 times lower.

Settings → SIM- Maps and Mobile Networks → [Select SIM] → Network Type → Only 4G

Disable "Smart switching of networks"

Enable VoLTE and VoWiFi (if available)

Install “4G only” in the network type

Check the signal level in NetMonster

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3. Engineer Mode: Secret settings for advanced

If the basic settings didn't work, it's time to get into Engineer Mode, a hidden menu for engineers where you can fine-tune the communication module.

To open Engineer Mode:

  1. Dial on the phone keyboard: ##4636##.
  2. Select the item Phone Information.
  3. Scroll down to the Set preferred network type block.

The following parameters should be set here (if they are different):

  • 🔧 Set preferred network type: LTE only (prohibits switching to the 3G/2G).
  • 📡 Enable LTE only: Include (if there is such a paragraph).
  • 🔄 LTE Band Selection: Select all available ranges (e.g., Band Selection, B1/B3/B7/B20 for Russia).

Another important parameter is Network Selection, and if you have a weak signal, try manually selecting the operator's network:

  1. In Engineer Mode, click Network Selection.
  2. Turn off Automatic and wait for the network scan.
  3. Select your operator manually (e.g., "MTS-RU" instead of "MTS").
What happens if the Engineer Mode does not open?
If the ##4636### code doesn’t work, try an alternative method: 1. Install the MTK Engineering Mode app from the Play Market (only for smartphones on a MediaTek processor like Redmi 9). 2. Open it and select MTK Settings. 3. Go to BandMode and set up LTE ranges manually.

4.DNS Change: Why It Speeds Up the Internet by 20-50%

DNS-Operator servers are often overloaded or slow, and are replaced by public servers. DNS (Google or Cloudflare can increase the speed of loading sites on the Internet. 20-50%, Especially if you are frequently using foreign resources.

How to change DNS to Redmi 9:

  1. Go to Settings → Connections → Private DNS.
  2. Select the host name of the private DNS provider.
  3. Enter one of the addresses: 🔹 Google DNS: dns.google or 8.8.8.8 🔹 Cloudflare: 1dot1dot1dot1.cloudflare-dns.com or 1.1.1.1. 🔹 AdGuard DNS (Blocking Advertising: dns.adguard.com

Save and restart the phone.

To check if the change has worked, use the DNS Checker app or run it in the terminal (via Termux):

nslookup google.com

If you see the answer, IP-address DNS (For example, 1.1.1.1 for Cloudflare, the settings are applied.

💡

For maximum effect combine DNS shut-off IPv6 in the mobile network settings (if your operator does not support it properly). → SIM-map → [Yours. SIM] → APN → Protocol APN → IPv4.

5.APN setup: why standard settings slow down speed

APN (Access Point Name is the gateway between your phone and the carrier's network. APN may limit the speed to 3G-level, even if you are connected to 4G. Redmi 9 is often confused by the parameters APN post-update MIUI.

How to set up your APN correctly:

  1. Go to Settings. → SIM-maps and mobile networks → [Choose. SIM] → Access points (APN).
  2. Click on the current APN (usually one) and select Delete APN.
  3. Create a new APN with your carrier’s settings (see the table below).
  4. Save and restart the phone.

Another common problem is Bluetooth conflict, and if you have Bluetooth enabled (for example, for headphones or smartwatches), it can interfere with your work. 4G-module due to interference in the 2.4 GHz range. Try to turn off Bluetooth and re-measure the speed.

💡

If the speed has not increased after all the manipulations, the problem may be a hardware malfunction (for example, an antenna dump or damage to the communication module), in which case only repairs in the service center will help.

FAQ: Answers to Frequent Questions

❓ Why is the Redmi 9 speeding? 4G lower than on the old phone?
Redmi 9 uses a Helio G80 processor, which has a weak network controller compared to flagships. In addition, MIUI by default restricts background data. Try the methods in Section 2 (Engineer Mode) and 4 (DNS). Also check if the power saving mode is on, it artificially limits speed.
❓ Can we disperse? 4G-Module of Redmi 9 without root?
Without root rights, you can't overclock a module, but you can optimize it. The most effective methods without root are: Change the LTE Band to Engineer Mode (section 3). Disable Smart Network Switching (section 2). Use a private DNS (section 4). These methods increase up to 30-50% without risk to the system.
❓ Why speed drops when I'm moving (in transport, on the street)?
This involves switching between towers. Redmi 9 has a weak module for handling handovers (transferring connections between base stations). Solutions: Enable Fast Dormancy option (if any) in Engineer Mode. Turn off automatic network selection and lock on one tower (section 3). Use the Network Signal Guru app to monitor switches.
❓ Does resetting to factory settings help?
Yes, but only if the problem is caused by a software failure (for example, after a failed update or installing "optimizers"). Reset will delete all APN, DNS and network profiles, returning them to default. Important: before reset, write down the current APN settings (section 5) - after resetting, you will have to reconfigure them.
❓ Why Speedtest shows 100 Mbps and files swing at 2 MBps?
Speedtest measures speed in megabits (Mbps) and files swing in megabytes (Mbps). To translate: 100 Mbps = 12.5 Mbps (100 ÷ 8). If Speedtest shows 80 Mbps, the real download speed will be ~10 MBps. If file download speeds are 30-50% lower, check DNS settings (section 4) and background restrictions (section 6).