heya 
This web tool makes it nice and easy! However I don't know if this site was up at the time so I just did it the old fashioned way with Microsoft's Hex Editor plugin for VS Code, which is still a perfectly cromulent option if you like to fine tune it that way.
Just open the .pal file (you could download a premade 54 byte template using the link above), press Open Anyway, then choose Hex Editor from the list that appears and go to town!
