Updating Android 6 to 7: safe transition to a new version

The transition from Android 6.0 Marshmallow to Android 7.0 Nougat is not just changing the number in settings, but a real improvement in the performance, security and functionality of your device. Even on older smartphones like Samsung Galaxy S6, Xiaomi Redmi Note 3 or LG G4 an update can give a new life: optimized memory management, split-screen multitasking mode and quick-response notifications. But the firmware process is fraught with risks - from data loss to complete “bricking” of the gadget.

In this article we will analyze all official and unofficial methods updates, dwell in detail on the preparation (backup, unlocking the bootloader, choosing firmware) and warn against common mistakes. We will pay special attention to devices for which the manufacturer stopped supporting updates via OTA here you will have to act manually. If your smartphone has never received Android 7 over the air, this does not mean that it cannot be updated!

Why is it worth upgrading from Android 6 to 7?

Android 7.0 Nougat brought changes that are still relevant for older devices:

• 🔄 Multitasking with split screen — work simultaneously in two applications (for example, YouTube + WhatsApp).
• 🔒 Improved security: monthly patches, kernel-level file encryption, protection against attacks via media files.
• ⚡ Doze on the Go — save battery even when the device is on the move (unlike Doze in Android 6, which only worked when completely stationary).
• 📱 Quick responses to notifications — respond to messages directly from the notification panel.
• 🎮 Vulkan API support —better graphics in games (if the hardware can handle it).

But not everything is so rosy: on weak devices (for example, with 1 GB RAM) Nougat may be slower than Marshmallow due to its heavier interface. Also, some manufacturers (like Huawei or Meizu) heavily reworked shells for Android 7, which led to bugs. Before flashing the firmware required check the reviews from users of your model!

Preparing the device: 5 mandatory steps

Firmware without preparation is like jumping from parachute without checking the lines. Even if you update official way (via OTA or proprietary utility), the risk of data loss or failure remains. Follow this checklist:

1. Backup

Use Google Account to synchronize contacts, calendar and some applications, but this is not enough. For a full backup:

• 📱 Local copy: applications like Swift Backup (requires root) or Titanium Backup will save application data.
• 💾 Files: copy folders DCIM, Downloads and WhatsApp to PC or cloud.
• 📞 SMS/calls: export via SMS Backup & Restore.

2. Checking the model and current firmware

Not all devices support Android 7. For example, Samsung Galaxy J3 2016 has not officially received the update, while Xiaomi Redmi 3S has received it, but only in some regions. Find out the exact information:

1. Go to Settings → About phone.
2. Write down Model device (for example, SM-G930F for Galaxy S7) and Build number.
3. Check support on sites like GSMArena or forums 4PDA, XDA-Developers.

Update methods: which one to choose?

The choice of method depends on two factors: Is the firmware official? for your model and Is the bootloader unlocked. Below is a comparison of all options:

Method	Requires a PC?	Reset data?	Brick risk	Suitable for
OTA (by air)	❌ No	❌ No	⚠️ Minimal	Device with official support
Proprietary utility (Odín, Mi Flash)	✅ Yes	✅ Yes	⚠️ Average	Samsung, Xiaomi, LG
ADB Sideload	✅ Yes	❌ No	⚠️ Low	Devices with an unlocked bootloader
Custom recovery (TWRP)	✅ Yes	✅ Yes	❗ High	Advanced users

OTA update is the safest method, but it is only available if the manufacturer has released firmware for your model. Check this:

1. Connect to Wi-Fi.
2. Go to Settings → About phone → System update.
3. If there is an update, download and install (the device will reboot several times).

If there is no OTA, you will have to use manual methods. For Samsung this is a utility Odín, for Xiaomi — Mi Flash Tool, for other brands - Fastboot or SP Flash Tool. Detailed instructions for each brand are in the following sections.

What is a “brick” and how to avoid it?

Brick is a condition when the device does not turn on or boots only into recovery/bootloop mode. Reasons: interrupted firmware, incompatible software version, errors when unlocking the bootloader. To minimize risks, always check the hash sums of downloaded files and do not interrupt the process!

Firmware via Odín (for Samsung)

Utility Odín —a standard tool for flashing devices Samsung. It works even if OTA update is not available, but it requires exact firmware version for your model. An error in selecting a file can lead to the loss of IMEI or a brick!

Step 1. Download the firmware

Official firmware for Samsung search on sites:

• 🌍 SamMobile (registration required, download speed is limited).
• 🌍 Sammobile Firmware (alternative source).
• 🌍 Updato (paid, but fast).

The firmware file usually has the format .tar.md5 and weighs 1.5–3 GB. Do not unpack it!

Step 2. Install drivers and Odín

1. Download Samsung USB Drivers from the official website.
2. Install Odín3 v3.14.1 (latest stable version).
3. Disable the antivirus - it can block the utility.

Step 3. Firmware

1. Turn off the phone and press Volume down + Home + Power to log in Download Mode.
2. Connect the device to the PC - a message should appear in Odín Added!!.
3. In the field AP select the downloaded firmware file.
4. Click Start and wait for completion (5-10 minutes).

⚠️ Attention: On some models Samsung (for example, Galaxy Note 7) the firmware through Odín resets the counter Knox, which will void the warranty. Check the status Knox in Download Mode —if there Knox: 0x1, the warranty is already lost.

Firmware via Fastboot (universal method)

Fastboot is a bootloader mode that allows you to flash system partitions directly. It works on most devices (except Mediatek and some Samsung), but requires unlocked bootloader. For Xiaomi, Google Pixel, OnePlus and other brands with an open policy, this is the best option.

Step 1. Unlock the bootloader

The process is different for each brand:

• 📱 Xiaomi: get permission in Mi Unlock Tool (link to account, wait 7-15 days).
• 📱 Google Pixel/Nexus: enable OEM Unlock in Settings → For developers.
• 📱 OnePlus: use the command fastboot oem unlock.

Step 2. Install ADB and Fastboot

Download Platform Tools from the site Android Developers and unzip to the root of the disk C:\platform-tools. Check the operation with the command:

fastboot devices

If the device is displayed, the drivers are installed correctly.

Step 3. Flash the image

For Android 7 you need a firmware file in the format .img (for example, system.img, boot.img). Commands for flashing:

fastboot flash boot boot.img
fastboot flash system system.img
fastboot flash recovery recovery.img
fastboot reboot

⚠️ Attention: On devices with a partition vendor (for example, Xiaomi on Qualcomm) an additional command is required fastboot flash vendor vendor.img. Without it, the system will not boot!

Solving errors during firmware

Even if you follow the instructions exactly, problems may arise. Here are the most common errors and their solutions:

Error	Cause	Solution
ODIN: FAIL! (Auth)	Incompatible firmware or locked bootloader	Check the device model and firmware version. Samsung may require a patch Pit.
Fastboot: remote: not allowed in locked state	The bootloader is not unlocked	Run fastboot oem unlock (the data will be erased!).
Error 7 in TWRP	Incompatibility of firmware with the device	Check the version TWRP and firmware. Sometimes it helps to disable the check in install.zip.
Endless loading (bootloop)	Error in boot.img or system	Flash the stock recovery and repeat the installation.

If the device does not turns on:

1. Try to go to Recovery Mode (Volume up + Power).
2. Reset (Wipe Data/Factory Reset).
3. If that doesn't help, flash the firmware again via Fastboot or Odín.

Loss of IMEI or network:

A common problem after flashing Samsung or Mediatek. Solved by restoring the EFSpartition:

• Download backup EFS for your model (look at 4PDA).
• Flash it through TWRP or Odín (in the field CP).
• Reboot the device.

Custom firmware: LineageOS and others

If there is no official update for Android 7, the only option left is custom firmware. The most popular:

• 🤖 LineageOS - pure Android with regular ones. updates.
• 🔧 Resurrection Remix —maximum customization.
• ⚡ Pixel Experience —interface as on Google Pixel.

Advantages of custom firmware:

• ✅ Updates even for old devices.
• ✅ No bloatware (pre-installed applications).
• ✅ Improved performance.

Cons:

• ❌ Possible bugs (camera, Bluetooth, NFC).
• ❌ No official support (risk of bricking is higher).
• ❌Banking applications may not work (due to lack of SafetyNet).

How to install LineageOS:

1. Unlock the bootloader.
2. Install TWRP Recovery.
3. Download the firmware and GApps (Google services) from the site LineageOS.
4. In TWRP execute Wipe → Advanced Wipe (check Dalvik, System, Data, Cache).
5. Flash LineageOS.zip i GApps.zip.

⚠️ Attention: Custom firmware is often required monthly manual update for security. Without updates, the device is vulnerable to exploits!

FAQ: Frequently asked questions

Is it possible to upgrade from Android 6 to 7 without losing data?

Official OTA update saves data, but manual methods (Odín, Fastboot, TWRP) almost always require a reset. The exception is ADB Sideload for firmware marked "no-wipe". However, even in this case, we recommend making a backup: sometimes the system behaves unstable after updating without cleaning.

My device does not officially support Android 7?

If you need it critically. Nougat functions (for example, split screen or Vulkan), then yes. But keep in mind:

• Some applications (banking, Netflix) may not work due to lack of certification Widevine L1.
• The camera may work worse (there are no proprietary drivers).
• Automatic OS updates will stop - you will have to monitor releasing new versions manually.

For everyday use, it is better to stay on the stock firmware with root access and optimization via Greenify or Magisk.

After the firmware, the phone began to slow down. What should I do?

Possible reasons and solutions:

1. Insufficient memory: Android 7 requires more RAM. Close background applications or install Lite versions software (for example, Facebook Lite).
2. Bad firmware optimization: Try another assembly (for example, instead of Resurrection Remix install LineageOS).
3. Remains of the old system: Perform a full reset (Wipe Data) and flash the firmware again.
4. Thermal limitations: Install Kernel Adiutor and lower the maximum frequency processor.

How to return Android 6 if 7 works poorly?

A rollback is possible, but there are nuances:

• For Samsung: flash the stock firmware via Odín (look for the file marked "4-file" for a full recovery).
• For other brands: use Fastboot or SP Flash Tool with a full stock image.
• Attention: on some devices (for example, Xiaomi s Anti-Rollback) rollback is blocked by hardware - you will get a brick!

Before rollback, check whether your model supports downgrade on the forums.

Do I need to update to Android 8+ after switching to 7?

Depends on the goals:

• Android 8.0 Oreo brought background optimization (limiting background processes), but on weaker devices it may slow down more.
• Android 9+ required Treble (vendor/system separation), which is not available on older smartphones. Custom firmware for them is often built with bugs.
• Security: Android 7 is still receiving patches from LineageOS, but official support has long been discontinued. For online banking, it is better to use a device on the current OS.

If your smartphone is used as a spare or for simple tasks (calls, instant messengers), Android 7 is a good balance between functionality and stability.