Don’t use JAMMA power and external power at the same time!
Download the update all.sh here and put it in your scripts folder.
All-in-one script for updating your MiSTer. Contribute to theypsilon/Update_All_MiSTer development by creating an account on GitHub.
github.com
You can ssh into the mister from your PC over WiFi to save having to take the card out.
Or you can plug into a monitor or your arcade game to run the script there, but you’ll have to get the file on first. On the mister just go to scripts then update all.
Follow the config by changing the .ini file to your setup needs.
The wiki is pretty good and there are guides for using putty to ssh.