Bug #99

Thinkpad T420: Bluetooth indicator light is always on

Added by Duncan . over 3 years ago. Updated about 3 years ago.

Status:NewStart date:03/12/2017
Priority:NormalDue date:
Assignee:-% Done:


Target version:-


Commit: df96a702ba98c1b85e8b4657498e76ec9f543447
The image was flashed to the BIOS region only, leaving the me region, gbe region, etc alone. The entire flash was then dumped, then the me_cleaner script was applied, but the result was to my knowledge the same when I tested the resulting image originally. It is difficult to see how me_cleaner would affect the resulting image, as it doesn't touch Coreboot's code.

Model: Lenovo Thinkpad T420


  1. Basic issue.
    The bluetooth indicator LED is always turned on as long as the wireless kill-switch is not activated, even though the Bluetooth card was removed from the device. To my knowledge no wireless card is left in, since I disassembled the device in order to flash Coreboot.
    This includes SeaBIOS, where it should not (to my knowledge) be activated anyway.

  2. Expected behaviour.
    One would reasonably expect the bluetooth indicator LED not to be turned on until the operating system turns on, as the WiFi card indicator behaves. Removing the WiFi card does not solve the issue (in case the WiFi card has this functionality also).

  3. Comparison with manufacturer firmware.
    This behaviour was not present in the manufacturer's firmware. The bluetooth card had already been removed when the manufacturer firmware was tested.

The config is attached as a file.

coreboot.config - Config file (20.4 KB) Duncan ., 03/12/2017 09:46 PM


#1 Updated by Patrick Rudolph about 3 years ago

The schematics shows that the Wireless LED is shared between WIFI and WWAN.
Do you have replaced one of them with a custom module ?
Do you have had seperate bluethooth card ? Most WIFI cards have integrated bluetooth.

#2 Updated by Patrick Rudolph about 3 years ago

Do you have a BDC installed ?

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