I'm not sure how I missed the release of this English patch, but I'm glad I stumbled upon it!
That being said, I experienced this same issue when attempting to insert a disc art PVR to the CDI and then add it to my SD card using SD Card Maker. I originally thought something was wrong with the way I was re-building the CDI until I found this thread.
In the end, my solution was to use the original NTSC-J GDI, patch it, and create a new CDI per SEGA-SKY's original instructions (
https://segasky.itch.io/karous-eng-translation)
except this time using the fixed IP.BIN from the fixed CDI already shared on this thread.
So, for those of you who are fans of this game but would love a copy that contains disc art for GDMenu, follow the link below to my custom CDI.
Karous (English).cdihttps://drive.google.com/file/d/1cBM0O1mrsGgv6M__kccojilzL-vRbDh_/view?usp=sharing