i have lenovo tab s8 50lc and it does not have an os installed and when i try to flash a custom rom or even the stock rom it fails and it never boots .... i tried to put it into recovery and had twrp started from pc as it is not flashed on the device and i tried fastboot method using adb and it tells me that it is unauthorized as usb debugging is not turned on or the oem unlock option in dveloper options so could you please help me