With the computer cores it can be a bit involved getting stuff working. The BBC Micro core has a few complications and limitations.
There are a few solutions you can look at, depending on what you want and what you have.
Starting the second processor version
The games jukebox menu that you’re presented with as standard is practical for most games but does not work with the 6502 second processor active. So you get the Tube on! error.
If you get the Tube on! error use these commands to start the second processor version:
Variations
There are basically 3 versions to choose from:
1. BBC Model B version. Original and vanilla.
2. BBC Master version. Bit faster and more use of colour.
3. Second Processor version (with model B or Master). Even faster and more colours. Very similar to the Master version.
Saving games
If you have a secondary SD slot you can copy the boot.vhd to a secondary SD card, and rename it to beeb.mmb
The beeb.mmb on a secondary card is read/write so you’ll be able to save games.
If you don’t have a secondary SD card you can use an alternate core version that works with R/W disc images. See here:
viewtopic.php?p=46443#p46443
There has been a bit of improvement on the code recently reducing the graphics flicker. See here for these disc images:
https://www.bbcelite.com/compare/releases.html
Right on commander!