Latest working kernel version: 2.6.26 Earliest failing kernel version: 2.6.27-rc? The thinkpad_acpi module used to restore the state of the bluetooth switch. Now it's always enabled after module loading. I guess this has to do with the conversion to rkfill in 0e74dc2646db04b644faa8ea10ff4f408d55cf90
Fixed in thinkpad-acpi release 0.21-20081019.