I can confirm this on Ubuntu 9.10 beta. I have a RAID1 array with no separate /boot partition. At boot, the message "Grub loading." comes up and stays more than 10 seconds, then for half a second "biosdisk read error" is displayed and finally I can reach the menu, which works normally for both Ubuntu and Windows (which is on another, non-raid disk).
I can confirm this on Ubuntu 9.10 beta. I have a RAID1 array with no separate /boot partition. At boot, the message "Grub loading." comes up and stays more than 10 seconds, then for half a second "biosdisk read error" is displayed and finally I can reach the menu, which works normally for both Ubuntu and Windows (which is on another, non-raid disk).