Erasing unused partitions/Custom formatting

WARNING: After performing these steps, it will be IMPOSSIBLE to run ANY downstream OS, including, but not limited to MIUI stock ROMS, ANY custom Android ROMs, ANY Halium-based Linux distro, or anything else not using a MAINLINE Linux kernel.

It is safe to wipe partitions /dev/mmcblk0p23,/dev/mmcblk0p25,/dev/mmcblk0p27-29 without any harm being done to the bootloader. Erasing these partitions will leave only mainline kernels bootable.

If you dont need recovery mode you also could remove /dev/mmcblk0p26 and /dev/mmcblk0p24.

If you dont need android boot partition you also could remove /dev/mmcblk0p22.

Reverting to stock from this setup

To revert to stock, Download the stock rom and flash it via fastboot(Not lk2nd fastboot).