Got it! Found the reason and a fix for it. Just not easy to find. It is an dependency-problem!
What happened? Well, in ~config/mylist.list.chroot I added the package "bootcd", which shoul exist in my live- system. During build this made no problems and all dependencies are ok. But - during install it appears, that there is a dependency conflict with the installer as bootcd needs grub-efi-amd64- bin. However, when bootcd wants to install, this package will be installed, too as it is dependent. So far, so well. BUT - grub-efi-amd64-bin conflicts with grub-efi-amd64-bin-signed and forces it to deinstall, which, you guess it, the debian-installer needs. And so the grub-installer crashes! Now the question, who should be asked for help? Maintainers of bootcd? Maintainers of debian- installer? Or Maintainers of packages? I do not know, and as long as I do not know, I can not file a bugreport as none of them (and this is fully correct and understandable) is responsible from his sight on. However, the problem can easily be reproduced. Thanks for reading this, hope it helps. For me, this issue can be closed. Best regards Hans
