Bluetooth mangoH yellow launch

You mean you’re running bluetoothctl? Works for me:

root@swi-mdm9x28-wp:~# bluetoothctl
Agent registered
[CHG] Controller 3C:E1:A1:E8:B6:E1 Pairable: yes
[bluetooth]# power on
Changing power on succeeded
[CHG] Controller 3C:E1:A1:E8:B6:E1 Powered: yes
[bluetooth]# exit             
root@swi-mdm9x28-wp:~# cm info
Device:                        WP7702
IMEI:                          352653090190778
IMEISV:                        4
FSN:                           4L931585051610
Firmware Version:              SWI9X06Y_02.32.02.00 c2e98c jenkins 2019/08/30 07:28:21
Bootloader Version:            SWI9X06Y_02.32.02.00 c2e98c jenkins 2019/08/30 07:28:21
MCU Version:                   002.013
PRI Part Number (PN):          9909138
PRI Revision:                  001.001 
Carrier PRI Name:              SIERRA
Carrier PRI Revision:          001.027_000
SKU:                           1104405
Last Reset Cause:              Power Down
Resets Count:                  Expected: 379	Unexpected: 1
root@swi-mdm9x28-wp:~#