A huge thankyou to both timlah79 and delt31 - the amount of hours you guys have thrown into creating this package and yet not asking for a cent is a fantastic community spirit. Looking forward to getting out of covid lockdown next week and back to playing JP ... with the Ultimate Code

Unfortunately that is not possible, as the image (whether the official Stern or the custom audio & video) that is written to the SD card is the complete software package. This is why when Stern release a new version, Tim and Delt have to reapply their customisations and Stern don't make it easy as they change the locations of the audio and video clips between versions (seemingly to discourage those attempting customisations). I doubt that Stern would ever create an open format whereby audio and videos was separated from the gamecode to allow them to updated independently.

The image will fit on a 8GB SD card so no issues getting a larger capacity like 16GB (not 10MB ). A lot of people are running the Sandisk brand - there are a few types both Tim and Delt recommended SanDisk Ultra 16GB Class 10 SDHC https://www.amazon.com/gp/product/B0143RTB1E

Just a clarification, to play goat mode you either need the topper or Inside Connect (IC), so it is still somewhat unique. The way the f/w update description read, some initially thought that all machines would have access to goat mode but this is not the case.