Installed 3.4 successfully, it worked great. Then I decided to attempt to change the theme by pressing the right arrow buttons…big mistake. The old 3.0 had other themes like GT and Lincoln, etc. when I got to the test mode in 3.4, it was different. I pressed something and now my screen is oversized and I can’t get out of this mode. I tried to reinstall 3,4, but it failed. am I screwed?
As far as I know, whatever change you perform to the theme while in the test menus is temporary.
That would explain why leaving it alone “solved” it.
For permanent changes you need forscan.
If this happened right after upgrading from 3.0 to 3.4 without having performed a master reset then yes, we are in the realm of glitches…