In a nutshell u can follow these steps:
Description of the use of Apps2SD on Xiaomi phones
1. We have a Rooted Xiaomi Redmi Note 5 Pro phone with Magisk installed and custom recovery (for example Orange Fox 10.1) and MIUI 10.3.1.0 firmware Android 9 stable. How to organize full Android access to a flashcard is not discussed here. BusyBox must be installed on the system.
2. Since we will use the 2nd partition with the f2fs file system on the flashcard, we need to install a custom kernel with support for this file system (I don’t know if the stock kernel supports this file system, I don’t use it!). I am using the Ancient-EAS kernel which can be downloaded from the link Click here!... Install the kernel in the usual way as a zip archive through custom recovery. After installation, you need to boot into the system and reinstall Magisk, then reboot, this will increase the overall stability of the system!
3. Next, you need to install a Magisk module called Init.d Injector from the Magisk repository.
4. After that, we reduce the size of the first partition of the flashcard and create a primary second partition there and format it for the f2fs file system. I am using a 128 GB flash drive, the second partition is 32 GB.
5. Boot with the repartitioned flashcard, launch Apps2SD and mount the second section of the flashcard. The section should mount perfectly!
6. In the Apps2SD settings, in the "Set path su.d ..." parameter, set the path data / adb / post-fs-data.d
7. Check the box for "Get sleep ban"
8. Check the box "Use CP instead of RSync" ...
9. Check the "Backup Apps2SD database" checkbox.
10. The "Restart Apps2SD service" checkbox should be ticked.
11. After that, go to "Bind applications to SD card" and select "Recreate mount script". Select the f2fs file system and select the item "My device supports init.d" and create a script. To be honest, I didn’t create any scripts until I ran the mounts, I don’t know where, when and what scripts are created, so you can go through all the points for reliability, but you should create everything when you select init.d.
12. Find and save the scripts 00000000apps2sd-main.sh, 01apps2sdinit, apps2sh-mountscript.sh in the data / adb / post-fs-data.d and data / adb / service.d folders, and then give these files permission 755. Trace to give apps2sd permission 777 in the data / adb folder.
13. That's it, you can reboot the phone, the 2nd section of the sd card will be mounted at boot, you can go to Apps2SD and move custom applications to the 2nd section of the sd card!
NB: this was translated so caution is advised