Thanks @all!!!
EDIT:
What remains unclear for me is how to extract/alter uimg files. This don't work:
http://omappedia.org/wiki/Android_Ge..._for_debugging
Also, maybe usefull for you: here's a nice guide on how to run recovery image, etc. in QEMU:
https://balau82.wordpress.com/2010/0...t-on-qemu-arm/