I'm thank you very much for answer ! Mi 8

Hello everyone,
I'm sorry, 8'm bad English.
I'm Unlock my Xiaomi Mi 8, and install TWRP, I flashed miui eu dev v10 8.12.7.
But i want flash to miui eu stable. Im think miui dev have rollback protect is Android 9., Im downgrade to Android 8 Miui Eu stable v10 Android 8, there is damage my mi 8 ?
This is brick my phone ?