Looks like I'm able to reproduce this with Asus A8V, single SATA drive and karmic amd64 netboot on USB pen drive.
BIOS boot order was SATA hdd first. I used boot device selection menu (hit F8 during POST) to boot from pen drive. I did a fresh install using defaults (hit ret most of the time). Disk was non-partitioned. After partitioning step I noticed that pen drive was /dev/sda and hdd /dev/sdb. Reboot after installation gave black screen with a blinking cursor. Reboot from the pen drive gave "GRUB Geom Error" twice and a blinking cursor.
Looks like I'm able to reproduce this with Asus A8V, single SATA drive and karmic amd64 netboot on USB pen drive.
BIOS boot order was SATA hdd first. I used boot device selection menu (hit F8 during POST) to boot from pen drive. I did a fresh install using defaults (hit ret most of the time). Disk was non-partitioned. After partitioning step I noticed that pen drive was /dev/sda and hdd /dev/sdb. Reboot after installation gave black screen with a blinking cursor. Reboot from the pen drive gave "GRUB Geom Error" twice and a blinking cursor.