📱 CMF Phone 1 - Nothing OS B4.1-260812-1726 Changelog

Firmware bot

Feedback? On your device: Go to Settings -> System -> Feedback.
Firmware rollouts are usually staggered, meaning not all users will receive the update simultaneously. This approach allows us to monitor for any issues and ensure a smooth and stable deployment.

What’s New in This Update

General Improvements and Bug Fixes

📱 Improved lock screen stability for a more reliable unlocking experience.
💬 Fixed an issue where third-party notifications could crash unexpectedly in certain scenarios.
⚙️ Enhanced overall system stability.
🛡️ Updated to August 2026 security patch.

Notes:
Your device may use more power and feel warmer during installation. Performance will return to normal after the update is complete.

jbtzn

Bugs were not fixed in this update. Is this how Nothing treat their budget lineup?

Borderlands

Hi everyone,

I’m facing a serious issue with my CMF Phone 1 running Nothing OS 4.1 / Android 16, build:

Tetris-B4.1-260812-1726

The phone is currently locked and I cannot access my data.

Before this happened, the phone repeatedly showed:

System UI keeps stopping / System UI isn’t responding

I received the Close app / Wait options several times. After some restarts, the phone eventually booted normally, but the problem with the PIN started afterward.

The problem

The phone asks for the PIN after reboot, as expected.

I know my 8-digit PIN and have not intentionally changed it.

When I enter the PIN:

All 8 digits are accepted.

The 8 PIN dots appear normally.

However, the phone does not unlock.

After repeated attempts, it eventually shows “Try again in XX seconds.”

I have carefully re-entered the known PIN multiple times.

I also tested with a USB OTG mouse to rule out a touchscreen/keypad problem. The mouse works and I can enter the PIN, but the phone still doesn’t unlock.

Things I have already tried

Normal restart

Forced restart

Safe Mode

Entering the PIN using the touchscreen

Entering the PIN using an OTG mouse

Completely draining and recharging the phone

Stock Recovery

Fastboot diagnostics

Safe Mode made no difference.

I have NOT:

Factory reset the phone

Selected Wipe data

Unlocked the bootloader

Flashed firmware

Erased userdata

Used any PIN-bypass/exploit tool

The bootloader is still locked.

Fastboot currently reports:

product: k6878v1_64

secure: yes

slot-unbootable:a: no

I also checked ADB, but the phone isn’t exposed through ADB, including in stock Recovery.

My main concern

I have important data on the phone that I don’t want to lose.

I don’t want to factory-reset the device unless there is absolutely no other option.

Has anyone with a CMF Phone 1 experienced the exact situation where the complete correct PIN is accepted as input but Android refuses to unlock the phone after System UI crashes/restarts?

If so:

Did the phone eventually accept the PIN again?

What fixed it?

Was there a particular Nothing OS update or lock-screen bug involved?

Is there any official Nothing diagnostic/maintenance procedure that can diagnose or repair the lock-screen problem without wiping userdata?

Has Nothing support or an authorized service center been able to resolve this while preserving the data?

I’m specifically looking for data-preserving solutions. Please don’t suggest factory reset unless there is no alternative.

Any help from Nothing/CMF engineers or users who experienced the same issue would be greatly appreciated.

Thank you.