Hey! That is super nice of you! Don't worry if it's too much work. I can try to figure it out. Sometimes I just feel so lost with this custom ROM stuff but I'm so happy I decided to start modding even if I get a few bricks

. You guys are great!!!
Okay, so you need:
- MiFlash, for example this version:
https://www.mediafire.com/file/md2c3alvuj5zlol/MiFlash2018-5-28-0.zip/file
- Fastboot and ADB:
https://www.xda-developers.com/google-releases-separate-adb-and-fastboot-binary-downloads/
- Some recovery, for example OrangeFox:
https://forum.xda-developers.com/t/...dmi-note-9-4g-redmi-9t-poco-m3.4257459/unread
- Latest stock:
https://xiaomifirmwareupdater.com/miui/lime/ (depends which region you have)
- Miui 21.x.xx using Android 11.0 (depends on your region and codename again)
- A custom ROM zip.
Soooo, lets go.
Turn off your phone, wait for 3 seconds, then press volume down and power buttons simultaneously until you see the fastboot logo (you won't miss it)
Connect the phone to the computer (do it fast, because the phone will turn off after a few seconds without being connected to the computer)
Back up all of the data on your phone if possible, then open MiFlash app, click refresh. Make sure your device is showing up.
Select your unpacked 12.0.90 or smething like that (miui 12, android 10) and flash it. Make sure you have ticked the clean all, not clean all and lock. Your bootloader should be unlocked.
Click flash.
Wait for the process to be finished
Flash the custom ROM
After your phone has rebooted successfully, turn it off and go into the fastboot mode again. Connect the phone to the computer
Launch the command line and go to the folder where you put your recovery.img from orangefox recovery, and boot it. (
https://wiki.orangefox.tech/en/guides/installing_orangefox)
You will see the recovery on your phone, probably prompting to enter the password. Choose "Cancel"
In the main menu, choose "Wipe", then tap "Format Data". Type "yes".
On your computer, copy all the ZIPs you've downloaded earlier to your phone.
wipe dalvik cache, cache and data.
Go to wipe > format data, type "yes" then click to proceed.
reboot to recovery, and flash xiaomi rom using miui 21.x.xx, based on android 11.
After flash, wipe cache, and boot your miui.
When booted, go to recovery, wipe dalvik cache, cache and data.
Flash your rom, and optional gapps and magisk.
Then reboot, that's all.