@rogeriol Please open a new topic and add the info requested in https://retropie.org.uk/forum/topic/3/read-this-first, don't bump old topics.

@mediamogul Mmmmm....I've tried different games but they all end the same. Maybe I should wait a little time for BlueMsx to become more powerful form the cassette point of view. Meanwhile I can use OpenMsx which works great!

Thank you so much!

The emulator itself supports both raw and .cas images.
I do not believe the scraper supports adding these images, so you would have to create a playlist manually.

The emulators.cfg can be modified to include the following commands:
-tape <filename> Attach cassette image (CAS format or raw file)
-boottape <filename> Attach cassette image and boot it
-tape-readonly Set the attached cassette image as read-only

I'd imagine it could work with this content in emulators.cfg:
atari800="echo %ROM: -\ % > /dev/null;/opt/retropie/emulators/atari800/bin/atari800 -config /opt/retropie/configs/atari800/atari800.cfg -boottape %ROM%"
default = "atari800"

Please note that i have not tried this myself.