guys,
HDMU images are created different way than others.
1-st kernel image file is named uImage.209 instead of uImage
2-nd kernel uImage file is expanded to be 8MB in size which is too big (and unnecessary)
The new version of DuckBA for Spark > 0.94 has workarround for those implemented. I checked at least with HDMU_635 and it worsk properly to me.