This is a character editor written in BASIC. Both layers are being used so all 256 characters in a font can be modified without affecting the program. The start-up of the program is slow due to character rom being written into layer 0 so it can be edited. Also had to clear layer 0 ram. Unable to use Try-In as program requires the the CHAR-EDIT-IF file. Once the program is loaded you can press L to load the EXAMPLE1 file so see an alternative character tile set.
Download the SD image to use. I've made an assumption about where the required interface data file is located and where the user data files will be.