with Auto Updated unchecked and set on Manual, you will see a message appear that an update is ready. That same message shows the release notes and an INSTALL button. It should not install until you click on that button, or exit the screen and go to Updates menu and install manually that way. But you should not be forced to install. I did look at that because I wanted to see how it was doing with old software (iptv app version) before I updated.
I have tried this a couple times and with Auto off, the update should not install until you direct it to.
Try to get it working on old software and with Manual Update enabled, then start up Live TV and when you see that message about new update, exit live TV (use the Back RCU button) and then Settings and into Update menu and try the update thru Manual option that way.
Just click it once and wait. It will seem like nothing happened, but wait. It will reboot on it's own and complete the update within 20 seconds or so.
Check results.