Freeminded.org

Kernel 2.6.20-13 On AMD64
Kernel 2.6.20-13 introduced strange behaviour with respect to nvidia drivers, causing the system not to boot. Reverting to drivers prior to -13 was working perfectly.
Kernel 2.6.20-15 fixes this.
From dmesg / /var/log/messages:

Apr 13 18:58:28 localhost kernel: [ 49.943586] **WARNING** I2C adapter driver [NVIDIA i2c adapter 0 at 7:00.0] forgot to specify physical device; fix it!
Apr 13 18:58:28 localhost kernel: [ 49.943634] **WARNING** I2C adapter driver [NVIDIA i2c adapter 1 at 7:00.0] forgot to specify physical device; fix it!
Apr 13 18:58:28 localhost kernel: [ 49.943655] **WARNING** I2C adapter driver [NVIDIA i2c adapter 2 at 7:00.0] forgot to specify physical device; fix it!

From -15 dmesg still reads the same message, but it is now harmless. Supposedly nvidia is working on this in their new driver release.

Modified partition table, now / is on a different partition
/etc/fstab uses UUIDs in Ubuntu Linux. You can find out your UUIDs by:
ls /dev/disk/by-uuid/

To obtain the UUID of a disk not in your list (the ‘new’ partition), do:
vol_id -u /dev/

Be sure to update /boot/grub/menu.lst to reflect these changes, otherwise your system will not boot, causing Error 22 on startup. Don’t dispair, Damn Small Linux can help you out.