thx arci - i thought there would be a way to analyze the kernel.img...
OK - then I mark the kernel version of the fullbackup using the kernel description (ULK for new, anything else for old kernels)...
only thing left: testing my fullbackup with azup
my new procedere:
- box in rescue mode? if no reboot to rm
- box overclocked? if yes switch it to normal mode and reboot
- enough ram available?
- started tool from /tmp? otherwise big warning for flashing
- check kernel CRC on PC
- check for same kernel CRC after uploading
- check for same kernel CRC after flashing (if it fails - install old kernel again)
- setting up environment for either old or new kernel
- flash image
- done