The checksum endianness for type=3ds courses is in Big Endian instead of Little Endian; it's correctly calculated, it just need to be properly byteswapped before writing it to the output.
For type=3ds courses converted from WiiU courses, the long (bottom) thumbnail is corrupted beyond recognition (the thumbnail seems to be properly scaled since it's visible on some levels that the outline of the original image is still present, it's just that the pixel data is messed up)
The checksum endianness for type=3ds courses is in Big Endian instead of Little Endian; it's correctly calculated, it just need to be properly byteswapped before writing it to the output.
For type=3ds courses converted from WiiU courses, the long (bottom) thumbnail is corrupted beyond recognition (the thumbnail seems to be properly scaled since it's visible on some levels that the outline of the original image is still present, it's just that the pixel data is messed up)