Hi Teo Oleo,
first of all thanks for the support and for the report, which allowed us to make the game compatible on the 500 mini. ;)
Regarding WHDLoad games loaded externally from USB, the best solution to make them compatible with the system would be to insert the whdload entry and data into the XML database found inside the THEA500 WHDLoad package, because the one available on the official website, which is here:
https://retrogames.biz/support/thea500-mini/whdload/
is not updated in real time and obviously cannot contain any XML entry about whdload exclusives released by our Team.
Of course, adding entries to the database is a manual operation that is difficult for users to apply, so in this case we simply solved it with a UAE configuration file to match the game, which also works with the ADF version (although for the 500 mini we recommend the Whdload version which is faster in loading).
In general, in our complete collections we have also implemented a specific version for the 500 mini with the XML database synchronized 1:1 with all the whdload titles (we talk about more than 5000 entries) that make up our catalog, including the exclusives.
If you want to know more about it or in any case want to download additional Amiga Vault wonderful exclusives you can find only on our catalogs we invite you to join the Facebook group dedicated to our project, available at the following link:
https://www.facebook.com/groups/amigavaultproject
Thanks again and have fun with Mundialito and the 500 mini! :)