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Fastboot Guide

Fastboot is the bootloader protocol used to query device state, boot temporary images, and flash bootloader-visible partitions.

On Curtana, Fastboot is essential for:

  • Checking bootloader unlock state.
  • Booting OrangeFox/TWRP temporarily.
  • Flashing recovery.
  • Recovering from some bootloops.
  • Entering FastbootD for dynamic partition operations.
  • Returning to stock with official Fastboot ROM scripts.

Fastboot vs ADB vs recovery

Android booted
  -> adb works
  -> fastboot does not work

Bootloader Fastboot screen
  -> fastboot works
  -> adb does not work

Recovery booted
  -> adb may work
  -> fastboot does not work unless recovery exposes a reboot path

FastbootD screen
  -> fastboot works
  -> used for userspace dynamic partitions

Run commands only in the mode expected by the guide you are following.

Verify Fastboot

Boot to Fastboot:

scripts\adb\reboot_bootloader.bat

Verify:

scripts\fastboot\verify_fastboot.bat

Manual equivalent:

fastboot devices
fastboot getvar product
fastboot getvar unlocked
fastboot getvar current-slot

fastboot getvar often prints to stderr; that is normal.

Device identity

Useful variables:

fastboot getvar product
fastboot getvar unlocked
fastboot getvar current-slot
fastboot getvar anti

Interpretation:

Variable Meaning
product Bootloader-reported codename. Curtana may report curtana or miatoll.
unlocked Whether bootloader is unlocked. Custom flashing requires yes or true.
current-slot A/B slot if exposed. Curtana workflows can still involve slot-aware packages.
anti Anti-rollback index when exposed. Downgrades require caution.

If product is not expected, stop. Do not flash while guessing.

Boot a recovery image temporarily

Temporary boot is the safest first recovery test:

scripts\recovery\boot_orangefox.bat recovery\orangefox\orangefox.img

Manual:

fastboot boot recovery\orangefox\orangefox.img

This loads the recovery image into memory. It does not write the recovery partition. Use it to confirm compatibility before flashing.

Flash recovery

After temporary boot is confirmed:

scripts\recovery\flash_recovery.bat recovery\orangefox\orangefox.img

Manual:

fastboot flash recovery recovery\orangefox\orangefox.img
fastboot reboot recovery

Boot directly into recovery after flashing. Some stock systems restore stock recovery during normal boot.

Unlock state

Check:

scripts\fastboot\unlock_status_check.bat

The script runs both:

fastboot getvar unlocked
fastboot oem device-info

Typical Xiaomi output includes:

Device unlocked: true
Device critical unlocked: true

Exact wording can vary by bootloader version.

Fastboot flashing risk model

Fastboot can write partitions with very little context. That makes it powerful and dangerous.

Low-risk read-only commands:

fastboot devices
fastboot getvar product
fastboot getvar unlocked

Medium-risk commands:

fastboot boot recovery.img
fastboot reboot
fastboot reboot recovery
fastboot reboot fastboot

High-risk commands:

fastboot flash recovery recovery.img
fastboot flash boot boot.img
fastboot erase userdata
fastboot wipe-super

Critical-risk commands:

fastboot flash xbl xbl.elf
fastboot flash abl abl.elf
fastboot flash modem NON-HLOS.bin
fastboot flashing lock

Do not flash bootloader, modem, or critical firmware partitions unless you are following a trusted stock restore package for the exact variant.

FastbootD handoff

Enter FastbootD:

fastboot reboot fastboot

The device screen should change from the bootloader Fastboot screen to a userspace FastbootD screen. See FASTBOOTD_FIX.md for the dedicated guide.

Common failures

waiting for any device

Likely causes:

  • Wrong mode.
  • Bad driver.
  • Bad cable.
  • USB hub instability.
  • Old platform-tools.

Fix:

Confirm phone is on Fastboot screen
  -> check Device Manager
  -> install Android Bootloader Interface driver
  -> try rear motherboard USB port
  -> update platform-tools

FAILED (remote: Flashing is not allowed in Lock State)

The bootloader is locked. Unlocking requires Xiaomi's official unlock flow and wipes data.

Do not try to bypass this with random scripts. Bypass attempts can make the device unrecoverable.

FAILED (remote: partition not found)

Likely causes:

  • Wrong partition name.
  • Trying to flash a dynamic logical partition in bootloader Fastboot instead of FastbootD.
  • Package intended for another device.
  • Recovery/ROM instructions not followed.

FAILED (remote: size too large)

Likely causes:

  • Image does not match partition.
  • Sparse image expected in FastbootD.
  • Wrong device build.
  • Outdated Fastboot binary.

Real-world examples

Recovery first boot

scripts\fastboot\verify_fastboot.bat
scripts\recovery\boot_orangefox.bat C:\Android\orangefox.img

Expected: phone leaves Fastboot and boots OrangeFox.

Recovery permanent install

scripts\recovery\flash_recovery.bat C:\Android\orangefox.img

Expected: script asks for FLASH, writes recovery, then attempts to reboot recovery.

Move to FastbootD

fastboot reboot fastboot
fastboot devices

Expected: device appears in FastbootD and remains visible to fastboot devices.

Logging

When asking for help, capture sanitized output:

fastboot devices
fastboot getvar all 2> logs\fastboot-getvar-all.txt

Remove serial numbers, IMEI, token values, and account identifiers before sharing.