Debian installer problem with GRUB

OpenMediaVault is using the Debian installer d-i to install the core system. The install process is preseeded to reduce user interaction and to do not allow the user to choose incorrect settings. While testing i realized that the installation of GRUB fails when the following parameters are given:

  • The system is installed on sde for example
  • sda-sdd are empty disks

In this case the installation fails with the message that it is not possible to install GRUB on sda. What? sda? I have choosen /dev/sde to install the core system. Why the hell is GRUB trying to install itself on sda?

Is this a bug or do i miss something?

The following options are used in the preseed.cfg file:

Any tipps or suggestions?

Update:
The bug also appears when using the latest Squeeze netinst ISO. A bug has been reported to Debian grub-installer package.