Tweak geometry not working

[retrorepair]

I've got an issue where I can't get into the tweak geometry settings to shift the image to the left. Every time I select it, no matter the video backend, I get a black screen and no way to exit so have to reset the machine.

Is this maybe related to the issue from a while ago with exclusive video mode causing a black screen? Although I'm fully up to date and not got this issue with anything else, just the tweak geometry setting.