If you have a specific demo you want to run I can take a look. Please post a link to the dsk/zip of the specific demo.
Not sure what your post of the Powergraph has to do with this?
I'm just wondering if this hardware has a connection.
But no, I unplugged Powergraph and still some demos don't work.
I will send the link to you by email.
sent to your email
So probably the only way to run such demos on msx is to unzip the DSK files and put the files in a directory, these files then work without any problems in SX-1
For example, DiskExplorer (https://hp.vector.co.jp/authors/VA013937/editdisk/index_e.html) can be used for extraction.
or Disk-Manager (http://www.lexlechz.at/en/software/DiskMgr.html)
Then save the files to the SD card in the directory and insert them into the SX-1, then they can be run using SofaRun.