Noting sporadic failures when attempting to connect the connex bt400 via Bluetooth serial profile to other devices we tried to lower the HCI UART speed by the line in the /etc/default/Bluetooth file HCIATTACH_SPEED=230400 (by default it is 921600).  Well we did that rebooted and Bluetooth disappeared.  HCITOOL DEV showed no devices.  We went back and set the speed to the original value and still no Bluetooth.  We did the same thing on another gumstix and again we killed (permanently) the Bluetooth capability.  Any ideas? We even reflashed the devices but still no Bluetooth.