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FASTBOOTPartitionsDestructive

fastboot format:ext4 userdata

Format userdata partition with filesystem

Destructive Operation WarningDestroys existing partition filesystem and all stored contents.
What It Does

Formats and creates a fresh filesystem (ext4 or f2fs) on the userdata partition. Essential when removing encryption or switching filesystem types.

Command Syntax
Terminal
$fastboot format[:<fs_type>] <partition>
Parameters & Placeholders Breakdown

This command syntax includes specific placeholder tokens. Below is an explanation of what each word represents and concrete real-world values to replace it with:

<fs_type>Vertical Screen Coordinate

The vertical pixel coordinate (Y-axis) from the top-left corner of the touchscreen.

Real-world value:1200
Command syntax: adb shell input tap 540 1200
<partition>Hardware Block Partition Name

The specific storage partition table name on the device (e.g., boot, init_boot, recovery, vbmeta, system, product).

Real-world value:boot or recovery or vbmeta
Command syntax: fastboot flash boot magisk_patched.img
On A/B slot devices, Fastboot automatically appends your current slot (e.g. boot_a).
Usage Examples
$fastboot format:ext4 userdata
$fastboot format:f2fs userdata
Options & Flags
Flag / ParameterDescription
ext4Format with fourth extended filesystem.
f2fsFormat with Flash-Friendly File System.
OFFICIAL COMPANION GUIDE

Flashing Generic System Images (GSI) / Project Treble?

Learn how to enter fastbootd, erase and resize logical dynamic partitions, and disable dm-verity with the complete handbook by @mkr-infinity:

Open GSI Flashing Guide
Prerequisites & Requirements
  • Unlocked bootloader
Related Commands
fastboot erase userdata

Erase user data partition (Factory reset)

Found an error or missing flag for fastboot format:ext4 userdata?

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