I also managed to get rid of this problem, though it wasn't trivial.
After updating to 2.6.28-15, I edited /etc/mdadm/mdadm.conf with ARRAY statements listing all my arrays (including the array for my root file system). Then, I did "dpkg-reconfigure initramfs-tools" to recreate the RAM disk image with the new mdadm.conf. After doing all this, I was able to boot straight into my root RAID array, without requiring rootdelay=, and without having to type any busybox shell commands.
The "dpkg-reconfigure initramfs-tools" was the non-obvious step for me. Until I did this, my changes to the mdadm.conf file would not show up in anything I did in the busybox shell.
I also managed to get rid of this problem, though it wasn't trivial.
After updating to 2.6.28-15, I edited /etc/mdadm/ mdadm.conf with ARRAY statements listing all my arrays (including the array for my root file system). Then, I did "dpkg-reconfigure initramfs-tools" to recreate the RAM disk image with the new mdadm.conf. After doing all this, I was able to boot straight into my root RAID array, without requiring rootdelay=, and without having to type any busybox shell commands.
The "dpkg-reconfigure initramfs-tools" was the non-obvious step for me. Until I did this, my changes to the mdadm.conf file would not show up in anything I did in the busybox shell.