Can I downgrade PIE to Oreo on U11 Dual SIM?

[loveuhp]

My device: U11 Dualsim Global version runing PIE 3.31.401.1 firmware.
Rooted, cusom recovery, unlocked BL.
2 choise I want to do:
1. un-root, relock BL, back to stock Recovery on PIE.
or
2. downgrade to Oreo, relock BL.
anyone help me!

 

[fabrizio b92]

My device: U11 Dualsim Global version runing PIE 3.31.401.1 firmware.
Rooted, cusom recovery, unlocked BL.
2 choise I want to do:
1. un-root, relock BL, back to stock Recovery on PIE.
or
2. downgrade to Oreo, relock BL.
anyone help me!

-check you CID
- Download RUU from here --->
- Use RUU Flash method to restore system