Rolling back Android 6.0 to 5.1 Lollipop: when it is necessary and how to do it safely

The transition from Android 6.0 Marshmallow back to Android 5.1 Lollipop is an atypical task that may be required in several cases: incompatibility of critical applications, decreased performance on weak hardware, or the need to use outdated functions removed in new versions. However, such a downgrade is associated with risks: from data loss to complete “bricking” of the device. In this article, we will look at when a rollback is justified, how to prepare for the procedure and what tools to use for different brands (Samsung, Xiaomi, Lenovo etc.).

It is important to understand: manufacturers rarely support official firmware rollback. Most instructions are based on unofficial methods that require unlocking the bootloader, installing a custom recovery, and manually flashing it. If you are not confident in your skills, consider alternatives: resetting to factory settings on the current version or using launchers with the interface Lollipop.

Before you begin, check whether your device supports rollback. For example, smartphones on chips Qualcomm Snapdragon 4xx/6xx series often allow downgrading, while devices with Mediatek Helio can block the installation of old firmware due to changes in preloader. Check compatibility on thematic forums (4PDA, XDA-Developers).

When Android rollback is justified: 5 good reasons

Firmware downgrade is a last resort. Consider it only in these cases:

• 🔄 Critical software incompatibility: applications for work (for example, 1C, specialized utilities for equipment) no longer support Android 6+.
• 🐢 Reduced performance: on weak devices (1 GB RAM, Quad-core 1.2 GHz) Marshmallow may work slower Lollipop due to background memory optimization Doze.
• 🔌 Problems with hardware: some modules (for example, NFC on old Sony Xperia) stop functioning correctly after the update.
• 🔒 Removing functions: in Android 6 separate APIs for automation have disappeared (for example, DeviceAdmin with extended rights).
• 🛠️ Repair or diagnostics: service centers sometimes require a rollback to test hardware components.

If your problem does not fall into this list, try alternatives solutions:

• 📱 Install launcher with interface Lollipop (for example, Nova Launcher with theme Material Design 2014).
• 🔧 Use Xposed Framework (if supported) to modify the current firmware.
• 🗑️ Perform reset to factory settings —sometimes this solves performance problems.

⚠️ Attention: Rolling back the firmware will void the warranty (if it is still valid) and may lead to loss of data in the section /data, including photos, messages and accounts. Create a full backup before starting the procedure.

Preparing for a downgrade: what needs to be done in advance

An unpleasant surprise: up to 30% of users trying to roll back the firmware encounter soft-brick (the device does not boot, but responds to PC connection). To minimize risks, follow these steps:

1. Check the model and version of the bootloader:

   Find out the exact model of the device in Settings → About phone → Model. For example, Samsung Galaxy J5 (2015) SM-J500F and SM-J500H require different firmware. The bootloader version (bootloader) can be seen in the fastboot command:

   fastboot getvar all

   If the bootloader version is newer than the target firmware, a rollback may not be possible without patching boot.img.

2. Download the correct firmware:

   Use only official or verified custom firmware from the forums. For Samsung — service Sammobile or Frija; for Xiaomi — Xiaomi Firmware Updater. Pay attention to the region (CSC): firmware for Europe (EU) may not be suitable for Russia (RU).

3. Create backup:

   Standard backup via Settings → Recovery and reset will not save everything. Use:

   • 📁 TWRP or OrangeFox Recovery for a full backup of the partition /data.
   • ☁️ Cloud services (Google Photos, Yandex Disk) for media files.
   • 📝 Titanium Backup (requires root) to save applications and their data.

Downloaded the firmware for the exact device model|

Created a backup via TWRP or Titanium Backup|

Checked the compatibility of the bootloader version|

Charged the phone at least 70%|

Installed ADB/Fastboot drivers on the PC -->

Pay special attention to the drivers: without correctly installed ADB and Fastboot drivers, the PC will not recognize the device in firmware mode. For Windows download Google USB Driver or package 15 seconds ADB Installer. On Linux/macOS usually there are enough standard rules udev.

⚠️ Attention: If your device uses FBE (File-Based Encryption), rolling back to Android 5.1 without decrypting the data will lead to its irretrievable loss. Check the encryption in Settings → Security → Encryption. On Lollipop the default is FDE (Full-Disk Encryption), with which compatibility is higher.

Rollback methods: official vs. unofficial

There are three main downgrade methods, differing in complexity and risks:

Method	Suitable devices	Risks	Necessary tools
Official rollback via OTA	Samsung, LG (rarely)	Minimum (if supported)	Smart Switch (Samsung), LG Bridge
Firmware via Odin/Flash Tool	Samsung, Mediatekdevices	Medium (risk of soft-brick)	Odin, SP Flash Tool, firmware in format .tar/.zip
Custom recovery + manual firmware	Any devices with an unlocked bootloader	High (hard-brick risk)	TWRP, ADB, Fastboot, patched boot.img

Let's look at each method in more detail.

1. Official rollback (if available)

Some manufacturers (for example, Samsung) periodically release rollback firmware to eliminate critical bugs. You can check their availability:

• 🔍 Via Smart Switch: connect the device to the PC → select Recovery → Update and initialize.
• 🌐 On the brand support site: enter the device model and look for the section Downgrade or Rollback.

If an official rollback is available, follow the manufacturer's instructions. Usually the process is automated and takes 10–20 minutes. Official rollback firmware saves data in the /data section, but resets the settings to factory settings.

2. Firmware via Odin (for Samsung)

For devices Samsung on chips Exynos or Snapdragon (except for models with a locked bootloader, for example USA version) the utility is suitable Odin. Procedure:

1. Download Odin3 (version 3.14.4) and firmware in format .tar.md5.
2. Run Odin, connect the phone to mode Download Mode (press Volume Down + Home + Power).
3. In Odin select the firmware files:
   • BL — bootloader (bootloader).
   • AP — main firmware.
   • CP — modem.
   • CSC —regional settings (select HOME_CSCto save the data).

Press Start and wait for completion (do not disconnect USB!).

⚠️ Attention: If in progress firmware Odin gives an error FAIL (Auth), which means the bootloader is locked. Try using patched firmware from the forums or contact the service center.

3. Manual firmware via TWRP

Universal method for most devices, but requires an unlocked bootloader and installed TWRP. Instructions:

1. Unlock the bootloader (for Xiaomi: fastboot oem unlock; for Google Pixel: via fastboot flashing unlock).
2. Install TWRP via fastboot:

   fastboot flash recovery twrp-3.6.0-0-your_model.img
   fastboot boot twrp-3.6.0-0-your_model.img

3. In TWRP execut Wipe → Format Data (required, otherwise the firmware will not install!).
4. Flash the firmware ZIP file via Install.
5. After installation, flash Magisk (if you need root) and Disable Force Encryption (if the firmware does not support FBE).

What to do if TWRP does not see the internal memory?

If after Format Data the internal memory is not mounted in TWRP, connect the device to the PC via USB and transfer the firmware to the SD card (if there is a slot) or use an OTG cable with An alternative is to flash it via ADB Sideload:

adb sideload your_rom.zip

Solving common errors when rolling back

Even if you follow the instructions exactly, problems may arise. Let's look at the most common ones:

Error	Cause	Solution
Error 7 in TWRP	Incompatibility of the firmware with the device or bootloader version.	Check the model and version bootloaderTry the firmware with the patch. no-verity-opt-encrypt.
Stuck on the logo after flashing	Incompatible boot.img or missing vendorsection.	Flash separately boot i vendor via fastboot:
SECURE CHECK FAIL: boot in Odin	Bootloader is locked (Knox, RMM).	Use patched firmware or roll back through a service center.
Loss of IMEI after flashing	Damaged partition modem or EFS.	Restore EFS from backup or flash separately modem.bin.

If the device does not turn on after an unsuccessful rollback:

1. Try logging in Recovery Mode (Volume Up + Power) and flash the firmware again.
2. If the screen is black, but the PC detects the device as Qualcomm HS-USB QDLoader 9008, use QFil or EDL Tool for emergency firmware.
3. For devices on Mediatek try SP Flash Tool with the option Format All + Download.

💡

If after the rollback the sensors (gyroscope, accelerometer) stop working, flash a separate file persist.img from the original firmware. It can be extracted from the full firmware package using 7-Zip.

Alternatives to rollback: how to do without downgrading

Rolling back firmware is a risky procedure. In most cases, the problem can be solved in other ways:

• 🔄 Disabling Android 6 functions:

  If the brakes are caused Doze, disable optimization for individual applications in Settings → Battery → Menu (⋮) → Battery optimization.

• 📱 Use of custom firmware:

  Firmware type LineageOS 12.1 (based on Android 5.1) offer stability Lollipop with security patches. Minus - an unlocked bootloader is required.

• 🖥️ Emulation of the old version:

  To test applications, use emulators (Genymotion, Android Studio) with an image Android 5.1.

• 🔧 Modification of the current firmware:

  Using Xposed or Magisk You can disable unwanted features Marshmallow (for example, dynamic rights management).

If the purpose of the rollback is to restore performance, try:

• 🧹 Clear cache via Recovery Mode (Wipe Cache Partition).
• 🚫 Disable animation in Settings → For developers (install Animation = 0.5x).
• 🔋 Replace the battery - a worn out battery can cause lags due to frequent mode switching energy saving.

💡

Before rolling back the firmware, always check whether the problem can be solved programmatically. In 70% of cases, alternative methods (reset, custom firmware, Xposed) give the same result without the risk of "bricking".

Risks and consequences of rolling back Android

Downgrading firmware is not a harmless procedure. Here's what to expect:

• 🔒 Locking the bootloader: some manufacturers (for example, Huawei, Motorolablock the ability to unlock again after a rollback.
• 📡 Problems with the network: Android 5.1 may not work with modern standards VoLTE or Wi-Fi 6.
• 🛡️ Security vulnerabilities: Lollipop has not received patches since 2017 Risk of exploits (for example, Stagefright) is increasing.
• 🔄 Problems with updates: after a rollback, OTA updates may not arrive or cause installation errors.

The most serious risk is hard-brick (complete failure of the device). This happens if:

• Flash an incompatible one bootloader.
• Interrupt the firmware process at the recording stage preloader (for Mediatek).
• Use firmware with a different type of markup (mtpartition).

If the device has become a "brick":

• For Qualcomm: try QFil or EDL Mode (authorized account required).
• For Mediatek: use SP Flash Tool with the option Format All + Download.
• For Samsung: flash 4-file firmware via Odin with a checkmark Re-Partition.

⚠️ Attention: Manufacturers can change the rollback support policy. For example, Samsung since 2022, it blocks downgrades on devices with Knox 3.7+. Before the procedure, check the current restrictions on the official website or forums.

FAQ: Frequently asked questions about rolling back Android 6 to 5

Is it possible to roll back Android without losing data?

Theoretically, yes, if use HOME_CSC in Odin or flash through TWRP without Format Data. However, in practice, this often leads to errors (for example, endless loading). We recommend creating a full backup and be ready to reset.

How do I know if my device supports rollback?

Check:

1. Availability of official rollback firmware on the manufacturer's website.
2. Reviews on the forums (4PDA, XDA) for your model.
3. Bootloader status: if it is locked (OEM Lock: Yes v fastboot), a rollback is unlikely.

What to do if the camera or sound does not work after a rollback?

This is a typical problem with incompatibility vendorpartition. Solutions:

• Flash separately vendor.img from the firmware.
• Install a custom kernel that supports your hardware.
• Return to Android 6 and use alternative methods (for example GCam for a camera).

Is it possible to roll back Android on a phone with root access?

root access simplify the process (for example, they allow you to create a full backup via Titanium Backup), but do not guarantee a successful rollback. The main thing is an unlocked bootloader. If you block it after getting root (for example, via fastboot oem lock), rollback will become impossible.

How to return Android 6 after an unsuccessful rollback?

If the device still turns on:

1. Download the full firmware Android 6 for your model.
2. Flash it through Odin/Fastboot with option Repartition (if available).
3. If the bootloader is damaged, use service utilities (Samsung: Z3X Box, Mediatek: SP Flash Tool).

If the device does not respond, contact the service center indicating the problem ("failed downgrade").