R4 Ultra Themes

Hey, long time lurker, first time actually posting. I have an R4 ultra, and I want to have some custom themes. I tried using a theme from NDSThemes, but I was met with a garbled-up menu. I put it in the theme folder for the current month, but I don't know what went wrong. Does R4 Ultra use separate themes, and if so, where can I get them?

EDIT: If this doesn't belong in here, please move it to the emulation/homebrew forum

maybe your themes are the wrong bitsize.
try opening the files in adobe photoshop, click save as and save them as 16bit bitmaps (.BMP's).