[Realme 7 Questions & Answers] said1219:
TL;DR: Removing com.coloros.weather.service through ADB and upgrading to Realme UI 2.0 will cause a flicker-brick on the lock screen.

Possible solutions:

Run adb shell cmd pm enable com.coloros.weather.service; will only work if you keep the USB debugging enabled and tick 'Always allow connection from this PC' during previous ADB sessions.

Wait for Realme to release an OTA to fix this problem. No one knows how long it will take to develop and propagate, no one even knows whether they see this issue yet, and once they saw it, no one knows whether they'll consider fixing it.

Quick wins:

How to allow running adb-command during this flicker-brick state? USB debugging is enabled; however, since I did not tick 'always allow', the device shows as 'unauthorized' on adb devices.

How to raise this issue to Realme? How to let their relevant (technical) team know about this problem? Usually, a case from customer service has to be escalated multiple times to reach the technical team.

Spoiler content hidden.

======================= Full issue description and analysis =======================​

Hi! I need some help regarding the "lock screen flicker" issue upon upgrading Realme 7 RMX2151 to Realme UI 2.0 (based on Android 11). The problem is widely known, and the suspected root cause is already found. However, I'm here to seek suggestions and ideas.

The issue is not specific to Realme 7; it generally applies to all Realme UI 2.0 upgrades. But since my device is Realme 7 RMX2151, I decided to post it here. The title might be a bit misleading since the flicker is unlike a CRT flicker, but simply the screen turns on and off frequently. To watch the issue:

Spoiler content hidden.

What still works:

Alarm works, also snoozing and dismissing them

Receiving and rejecting calls works, but the contact name won't appear since the phonebook is still encrypted

Pressing and holding the power button will trigger a grey rectangle that persists during the flicker

Pressing and holding power + volume up will reboot the device

Pressing and holding power + volume up + volume down will reboot the device into Recovery

The Recovery works perfectly, including OTA updates

The root cause is the removal of com.coloros.weather.service package. A user may choose to remove this package to 'debloat' their phone and remove the unused app. Little did they expect that this seemingly unimportant package will cause the lock screen flicker issue upon upgrade. This has been acknowledged by Mywk on his thread "[GUIDE][EU/IN ROM] REALME UI Debloat List"

Suggested solutions so far:

Enabling com.coloros.weather.service through adb

This solution only works if:

- you enabled USB debugging (a prerequisite for debloating through ADB) and

did not disable it afterwards

- you ticked 'always allow connection' (forgot the exact wording) when using adb to save the keys on the device

- some kind of luck that the device will allow debugging even though it had not been unlocked after the first boot

[CONFIRMED DATA LOSS] Get into recovery mode and wipe the device. However, some users reported that the issue persists after the device wipe unless the device is downgraded to Realme UI 1.0. For Realme 7 RMX2151 (non-EU), the official downgrade package can be downloaded here. Copy the ozip into the root of the SD Card and install it through Recovery. It is appropriately signed, so it can be used on stock recovery.

Wait for Realme to release an OTA update to fix this issue and make it available. It could take

months

for it to propagate, though. I'm not sure whether they are aware of this issue or think it is worth fixing (debloat = user's fault?)

[SUSPECTED DATA LOSS] Flash an ozip of the same or more recent firmware. The ozip flash feature of stock recovery does not clearly state 'Keep Data', unlike check OTA that says so directly under the command. But shouldn't an update ozip (to a more recent version, not a rollback) works like regular OTA?

[CONFIRMED PARTIAL DATA LOSS] Pulling the internal storade through recovery mode. App data will be lost.

This solution only works if:

- you enabled USB debugging (a prerequisite for debloating through ADB) and

did not disable it afterwards

- you ticked 'always allow connection' (forgot the exact wording) when using adb to save the keys on the device

Boot into recovery mode. Choose to install ozip from the device. Recovery will then ask for the device password to decrypt the internal storage. Do not choose any file. Connect the phone to the computer and do an adb pull.

Use a Boot ROM (BROM) exploit by Dinolek and k4y0z to inject the package com.coloros.weather.service. Or, in my specific case (USB Debugging enabled but RSA Public Key not saved on device), write the public key on /data/misc/adb/adb_keys.

However, I need more guidance on how to do this, as most tutorials I saw was to overwrite the phone with a custom ROM, while my current objective is to return my phone to normal function through reinstalling com.coloros.weather.service or at least decrypt the internal storage and pull the files out (app data will be lost). I cannot understand and adapt the tutorial to my objective or even know whether this BROM exploit will help me.

Possible outcomes:

Best scenario: You could magically issue an ADB command to reinstall com.coloros.weather.service in the flicker-bricked state. I did keep USB debugging enabled, but I did not save my computer's RSA key on the device; hence the device shows up as 'unauthorized' on adb devices. Any suggestions?

Not-so-bad: somehow, an ADB command could be issued in recovery mode or normal boot to pull the data. The same problem occurs: I did not save my computer's RSA key on the device; hence the device shows up as 'unauthorized' on adb devices. Any suggestions?

Another scenario: Realme realizes this issue and works on a fix. The fix is made available as an OTA and can be downloaded through recovery mode. Any ideas where to ask to increase the chance of this happening?

Worst case: wipe the phone, move on, and make amends with whatever App Backup, Google Photos, WhatsApp Cloud Backup, etc., successfully keep.