I expect that part isn't working, and isn't easily fixable... This is a tablet and some tablets commonly have a native screen orientation of portrait so that's probably what Plymouth is using.
When the gnome-shell login screen starts it detects the correct orientation and automatically rotates to landscape. So the issue sounds like Plymouth not supporting sensors/screen rotation. Not a very common issue... ** Changed in: plymouth (Ubuntu) Status: Incomplete => New ** No longer affects: linux (Ubuntu) ** No longer affects: iio-sensor-proxy (Ubuntu) ** Summary changed: - [Lenovo Ideapad D330] [bmc150] Problem with g sensor and screen orientation + Tablet (plugged into a folding keyboard) boots in portrait mode and doesn't rotate correctly to landscape until the login screen -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1873164 Title: Tablet (plugged into a folding keyboard) boots in portrait mode and doesn't rotate correctly to landscape until the login screen To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/plymouth/+bug/1873164/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs