The kernel that doesn't boot is 2.6.28-11.42, the previous kernel from Intrepid (which is left over from the upgrade) is 2.6.27-11.31, and still boots with ACPI enabled.
The kernel that doesn't boot is 2.6.28-11.42, the previous kernel from Intrepid (which is left over from the upgrade) is 2.6.27-11.31, and still boots with ACPI enabled.