How can i install DragonFlyBSD manually like it is stated in the bug report by using -C in fdisk?
What you can try is to 1) install normally via the installer and then after installation 2) login as root and do 'fdisk -BIC /dev/da0' (replace da0 with the disk you chose for installation).
This should work if you are installing dfly to the whole disk. Sascha
