Introduction to Dynamic Partitions on Android

Modern Android devices, particularly those launched with Android 10 or later, utilize a sophisticated partitioning scheme known as Dynamic Partitions. This system abstracts the physical layout of storage, replacing fixed-size partitions like system, vendor, and product with logical partitions contained within a single large ‘super’ partition. This flexibility allows for Over-The-Air (OTA) updates to resize partitions on the fly without requiring a full repartition, making updates more seamless.

However, this abstraction can be a double-edged sword for enthusiasts and power users. While beneficial for updates, the fixed allocation of logical partitions within the super block might not always align with your needs, especially when flashing custom ROMs, installing extensive Google Apps (GApps) packages, or simply wanting to reclaim unused space from a bloated system partition to expand user data. This guide will walk you through the expert-level process of manually resizing these dynamic partitions, empowering you to optimize your Android device’s storage layout.

Warning: Manipulating dynamic partitions carries significant risks, including data loss and potentially bricking your device if not performed correctly. A complete backup is not just recommended; it is absolutely mandatory.

Essential Prerequisites and Tools

Before embarking on this complex procedure, ensure you have the following tools and have completed the critical preparatory steps:

Required Tools

• Android Debug Bridge (ADB): For communicating with your device while it’s booted into Android or custom recovery.
• Fastboot: For communicating with your device while it’s in bootloader or fastbootd mode, essential for partition manipulation.
• Custom Recovery (e.g., TWRP, OrangeFox): A recovery environment that supports dynamic partition management and allows shell access.
• A Computer: With ADB and Fastboot drivers correctly installed.
• USB Cable: A reliable one to connect your device to your computer.

Critical Steps Before You Begin

1. Unlock Your Bootloader: This is a prerequisite for flashing custom recoveries or modifying partitions. Be aware that unlocking usually wipes all data.
2. Complete Nandroid Backup: Using your custom recovery, perform a full backup of all partitions, including internal storage, super, system, vendor, data, etc. Store this backup on your computer or an external storage device.
3. Download Necessary Firmware/ROMs: Have your preferred custom ROM, GApps, and any stock firmware images ready in case you need to revert.

Understanding Android’s Partition Layout and Logic

The core concept behind dynamic partitions revolves around the super partition. Instead of fixed partitions, the super partition acts as a container, dynamically allocating space to logical partitions such as system, vendor, product, odm, system_ext, and userdata. The actual size of these logical partitions can be adjusted without changing the underlying physical block device layout.

Many devices also employ A/B (seamless) updates, meaning there are two sets of most partitions (e.g., system_a, system_b) to allow updates to be installed in the background. While dynamic partitions enhance this, our focus will be on the currently active slots.

Key tools for this process include command-line utilities:

• lpmake: For creating new logical partitions.
• lpremove: For deleting logical partitions.
• lpresize: For resizing existing logical partitions within the super partition.
• resize2fs / f2fs_resize: For resizing the filesystem *inside* a logical partition (for ext4 and f2fs filesystems, respectively).

While lpresize is the fundamental tool, its direct use can be complex and risky. Often, users will leverage `fastbootd` commands or custom recovery features that abstract these operations.

Step-by-Step Guide: Resizing Dynamic Partitions

Our primary goal in most resizing scenarios is to shrink a system-related partition (like system or product) to free up space, which can then be used to expand the userdata partition for more app storage.

1. Boot to Fastboot Mode

Ensure your device is connected to your PC and recognized by ADB.

adb reboot bootloader

Or, power off your device and use the specific button combination for your device (e.g., Volume Down + Power).

2. Flash and Boot into a Compatible Custom Recovery

If you don’t already have one, flash a custom recovery that supports dynamic partition management. After flashing, immediately boot into it.

fastboot flash recovery recovery.imgfastboot reboot recovery

3. Identify Current Partition Sizes and Filesystem Information

Once in custom recovery, open an ADB shell to your device. This will give you a command-line interface to perform operations.

adb shell

Check the current partition layout and free space:

df -h /dev/block/mapper/*

This command will show you the mounted logical partitions and their sizes. Pay close attention to /dev/block/mapper/system, /dev/block/mapper/vendor, etc.

4. Plan Your Resize Strategy

Decide how much space you want to reclaim from which partition. For example, if your system partition is 4GB and you know a custom ROM only requires 2.5GB, you can shrink it by 1.5GB to free up space for userdata. Note down your target sizes.

5. Shrinking a Logical Partition’s Filesystem (e.g., system)

This step resizes the *filesystem* residing within the logical partition. This does not yet free up space from the super partition, but it prepares the logical partition for resizing.

First, ensure the partition you want to shrink is not mounted. Custom recoveries usually handle this, but you can explicitly unmount if necessary (e.g., umount /system).

Check the filesystem for errors (essential before resizing):

e2fsck -fy /dev/block/mapper/system

Now, resize the filesystem. Replace <new_size>M with your desired size in megabytes (e.g., 2500M for 2.5GB).

resize2fs /dev/block/mapper/system 2500M

If your partition uses F2FS, use f2fs_resize instead (syntax may vary slightly).

6. Adjusting the Logical Partition in the ‘super’ Block (The Crucial Step)

After shrinking the filesystem, you need to tell the super partition that the logical partition’s container is also smaller. This often requires rebooting to fastbootd mode.

exit # Exit adb shelladb reboot fastboot

Your device should now be in fastbootd mode (often indicated by