Hey - So because 'reasons' I have High Sierra installed on an unsupported RAID-O config in my iMac. (I made the raid, then carbon copy cloned a working macOS to it). That all works fine, but I can't update the core macOS.(it attempts, it looks like its done, it reboots, it hasn't done it). So my question is, if I boot from a USB installer made with 10.13.1 can I just update an existing install using the USB?