If you're using twrp from official site , that wouldn't work with android 10 ,download twrp FBE as mentioned in the post , also after flashing rom goto wipe > format data and type YesHi, coming from stock on my daughters phone, I unlocked the bootloader, installed twrp 3.3.1 and downloaded the latest magisk, recommended gapps and latest build. When I go to flash I repeatedly get the error at the end of flashing the rom zip 'unable to mount vendor, device not found'. Went back and downloaded the last factory image for angler and installed that and then from there went through the whole process again. Again the same error. Can anyone give me some advice on why I keep getting that error. I've googled it quite a bit and some of the things I see is about treble supported devices which angler is not one of them if I'm not mistaken. Any help would be appreciated. Thanks guys.