Yesterday i downloaded the 4.1.5 update via OTA installer in settings, moved the zip to my downloads, went to TWRP wiped data cache and dalvik and flashed it but it gave me an error 7. Currently I have a "Unable to mount /system" problem when i do anything in TWRP. My phone works with the nandroid back up i restored. Root works but the /system isn't mounted according to TWRP which worries me. I want to update to 4.1.5 in the end. Any ideas? Thanks.