Pi BeebIT Screen cropping

I am running a Pi with Maplin kit including powered hub, usb mouse and keyboard using HDMI to a Toshiba Flatscreen TV.

RiscOS is installed and is working with a monitor type of LCD 14500 1024×768 60Hz and the desktop is pretty clear and mostly fits the tv screen.

BeebIT is installed, working at a good speed and I can run various BBC Micro Games which look as good as I remember them on my Beeb and the sound and keyboard work fine.

However, when the RiscOS “BeebIT icon” is clicked and the screen changes to the BBC BASIC screen, the last couple of lines are lost. Then when I start a game, it is also truncated at the bottom, although everything else works as I would expect.

I have tried various config.txt changes, but these only seem to impact the RiscOS, where I am not having the cropping problem. I can force it not to crop BeebIT by selecting different monitor types and resolutions, including Generic, but to date if I always end up with a very squashed (widescreen) BeebIT image.

I have also tried changing the limited set of options on my TV including forcing 4:3 mode and using the video connector on my Pi to Video in rather than HDMI, but I get the same result.

Am I missing options somewhere to force RiscOS to give BeebIT a slightly larger window to work in or am I missing the point completely?

Any advice on what I might be doing wrong, or where I can research next please? Many thanks.

What is the native resolution of the screen?

Usually it is 1920 × 1080 which would be the mode you would want to use for a non-fuzzy and non-cropped display.

The TV Spec says the it is 1440×900 Pixels and this is where I started from. However, it also recommends PAL scan rates which include 720p and 1080i. The best result I have so far is 720p in config.txt with a RiscOS generic screen resolution of 1440×900. I am still not getting a true fit, and it is a bit fuzzy, but it is usable.

I want to look into the MDF settings, but I haven’t found out how to do that yet.

However, on advice from the BeebIt author, Michael Foot, I have changed the BeebIt screen option from Auto to High, and this has sorted out the truncation of the Beeb emulation screen.

Thank you for your help, much appreciated.