I tried to go back to nougat (my phone update to oreo 8.1) but when I tried the commands it sends errors:
Code:
(bootloader) is-logical:boot: not found
Sending 'boot' (16384 KB) OKAY [ 0.734s]
Writing 'boot' (bootloader) Security version downgrade
(bootloader) Image boot failed validation
(bootloader) Preflash validation failed
FAILED (remote: '')
fastboot: error: Command failed
On all these commands:
fastboot flash boot boot.img
fastboot flash recovery recovery.img
fastboot flash system system.img_sparsechunk.0
fastboot flash system system.img_sparsechunk.1
fastboot flash system system.img_sparsechunk.2
fastboot flash system system.img_sparsechunk.3
fastboot flash system system.img_sparsechunk.4
fastboot flash oem oem.img
Then the phone restarted as new, but now the finger sensor doesn't work.
Need some advice. I really want to get back to nougat, but if it's not possible, how could I fix the finger sensor?
Thank you!