Oreo to Nougat/MM

[TechGenius]

Can we downgrade oreo to nougat or marshmallow without any issues ?

 

[echo92]

If you do downgrade your stock (i.e. Motorola) firmware, there's a few things to bear in mind:
1) you will need an unlocked bootloader to downgrade firmware. The process of unlocking your bootloader will erase your device, so back up accordingly. If your SD card is adopted as internal storage, the encryption key for your SD card will be erased too. You'll lose your SD card data. Also, you will not be able to lock your bootloader unless you flash the latest stock firmware again (if you're on Oreo firmware, you can only use Oreo firmware)
2) downgrading is usually straightforward. However, you will not be able to downgrade your bootloader and GPT. For this reason, do not use OTA updates whilst downgraded with stock firmware. You'll likely hard brick your device.
3) instead of flashing the stock firmware, you could alternatively unlock your bootloader and then try the TWRP flashable firmwares https://forum.xda-developers.com/moto-g4-plus/development/rom-oreo-8-1-0-soak-test-t3873367 you will need the TWRP recovery, however TWRP flashables might be safer to use to downgrade than flashing stock firmwares.