[Xiaomi Poco X3 Pro] keypress:
hi everyone, sorry for writing that long message, but I'm a newbie in custom ROMs and I don't have it clear, what is the upgrade procedure from LAOS 18.1 to 19.1.

General instructions are given, but I don't know how to do some of these steps:

- https://wiki.lineageos.org/devices/vayu/upgrade

- https://xdaforums.com/t/rom-s-official-lineageos-19-1-for-poco-x3-pro-vayu.4301199/post-87005341

Some people had problems and I don't want to brick my phone...

- e.g. https://xdaforums.com/t/rom-s-official-lineageos-19-1-for-poco-x3-pro-vayu.4301199/post-87141839

I'd like to prepare more detailed instructions that would be helpful for other newbies like me. This way maybe one day LAOS will be as easy to install/upgrade, as Debian or Ubuntu are.

So I have an X3 Pro with a plain LAOS 18.1 + Gapps installed according to instructions from https://wiki.lineageos.org/devices/vayu/install :

- unlocked and installed everything about 2022-02-20

- firmware with baseband 1119_2217 - so it is 12.5.5.0.RJUEUXM Europe region (according to https://xdaforums.com/t/firmware-poco-x3-pro-vayu-bhima-auto-updated.4253099/post-87448127 )

- Lineage Recovery

- LineageOS 18.1

- OpenGApps

- not rooted

- no SafetyNet addons

I used adb and fastboot during my first installation and would prefer to continue that way.

I have never upgraded the firmware.

I'd like to avoid the factory reset or removing all my data from the phone.

So now - please forgive me my lack of knowledge of custom ROMs, and please tell me about the mistakes in the steps that I plan to do.. Especially those starting with "???".

Step #1: firmware upgrade

- Download the latest firmware in a ZIP file for Android 12 for Europe region from https://xiaomifirmwareupdater.com/archive/firmware/vayu/

- Verify its MD5 hash

- Start the phone in Recovery mode (refs: https://wiki.lineageos.org/devices/vayu/#special-boot-modes )

- On the phone select: Apply update => Apply from ADB

- Flash the firmware with adb:

adb sideload <firmware_filename>.zip

- ??? Should I reboot now using the Recovery option "Reboot system now", or should I reboot directly to fastboot mode by using `adb reboot bootloader`, or I can reboot to whatever I want ?

Step #2: recovery upgrade

- Download the latest recovery IMG file from https://download.lineageos.org/vayu

- Verify its SHA256 hash

- Start the phone in Fastboot mode (refs: https://wiki.lineageos.org/devices/vayu/#special-boot-modes )

- Flash the recovery with fastboot:

fastboot flash recovery <recovery_filename>.img

- Reboot the phone to Recovery mode (refs: https://wiki.lineageos.org/devices/vayu/#special-boot-modes )

Step #3: LineageOS upgrade

- On the phone select: Apply update => Apply from ADB

- Download the latest system package in a ZIP file from https://download.lineageos.org/vayu

- Verify its SHA256 hash

- Download the latest version of MindTheGapps for Lineage 19 for Android 12.1 for arm64 in a ZIP file from https://wiki.lineageos.org/gapps#mobile

- Verify its MD5 hash

- ??? Is it a problem that earlier I used OpenGapps and now I have to use MindTheGapps, because OpenGapps doesn't support Android 12?

- Install the packages with adb:

adb sideload <lineageos_filename>.zip
adb sideload <gapps_filename>.zip

- On the phone go back and choose "Reboot system now"

- Wait some minutes until the installation is finished.