I also have problems with getting Lakka (on rPi1) to detect my 8Bitdo NES30 and 8Bitdo SFC30 controllers when they are connected via Bluetooth (mode START and mode START+R), when connected via USB they works fine.
NB: I have made a custom RetroArch-AutoConfig-Folder on Lakka (rPi1) with added autocfg-files for 8Bitdo NES30 and 8Bitdo SFC30 controller connection variants.
My Sony PlayStation3 DualShock3 controller works fine via Bluetooth on Lakka (on rPi1).
My 8Bitdo NES30 and 8Bitdo SFC30 controllers works fine via Bluetooth (mode START and mode START+R) and USB on my Ubuntu PC (x64) with RetroArch and with the same added custom autoconfig-files for the 8Bitdo controller connection variants as I used on Lakka (rPi1).
Here is my results from testing:
# ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
# dmesg - Lakka - PS3
# Lakka-RPi.arm-devel-20150529164419-r21027-g43f71a8.img
[ 8486.150119] input: PLAYSTATION(R)3 Controller as /devices/platform/bcm2708_usb/usb1/1-1/1-1.3/1-1.3:1.0/bluetooth/hci0/hci0:41/0005:054C:0268.001C/input/input18
[ 8486.165737] sony 0005:054C:0268.001C: input,hidraw0: BLUETOOTH HID v1.00 Joystick [PLAYSTATION(R)3 Controller] on 99:88:66:00:23:48
[ 8546.402307] usb 1-1.2: USB disconnect, device number 11
[ 8578.609056] usb 1-1.2: new full-speed USB device number 12 using dwc_otg
[ 8578.724785] usb 1-1.2: New USB device found, idVendor=054c, idProduct=0268
[ 8578.724830] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 8578.724847] usb 1-1.2: Product: PLAYSTATION(R)3 Controller
[ 8578.724866] usb 1-1.2: Manufacturer: Sony
[ 8578.798900] input: Sony PLAYSTATION(R)3 Controller as /devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2:1.0/0003:054C:0268.001D/input/input19
[ 8578.810160] sony 0003:054C:0268.001D: input,hiddev0,hidraw0: USB HID v1.11 Joystick [Sony PLAYSTATION(R)3 Controller] on usb-bcm2708_usb-1.2/input0
[ 8589.416604] usb 1-1.2: USB disconnect, device number 12
# RetroArch = OK.
# ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
# dmesg - Lakka - 8Bitdo SFC30-USB
# Lakka-RPi.arm-devel-20150529164419-r21027-g43f71a8.img
# 8Bitdo Firmware v2.61 (2015-06-06).
[ 9078.642077] usb 1-1.2: new full-speed USB device number 14 using dwc_otg
[ 9078.739035] usb 1-1.2: New USB device found, idVendor=1235, idProduct=ab11
[ 9078.739075] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 9078.739091] usb 1-1.2: Product: FC30 Joystick
[ 9078.739106] usb 1-1.2: Manufacturer: FC30
[ 9078.789894] input: FC30 FC30 Joystick as /devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2:1.0/0003:1235:AB11.0020/input/input22
[ 9078.794883] hid-generic 0003:1235:AB11.0020: input,hidraw0: USB HID v1.10 Joystick [FC30 FC30 Joystick] on usb-bcm2708_usb-1.2/input0
# RetroArch = OK.
# Autocfg = https://github.com/libretro/retroarch-joypad-autoconfig/blob/master/udev/8Bitdo-SFC30-GamePad-USB.cfg
# ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
# dmesg - Lakka - 8Bitdo SFC30-BT(START)
# Lakka-RPi.arm-devel-20150529164419-r21027-g43f71a8.img
# 8Bitdo Firmware v2.61 (2015-06-06).
[ 9245.896820] hid-generic 0005:2810:0009.0021: unknown main item tag 0x0
[ 9245.911324] input: 8Bitdo SFC30 GamePad as /devices/platform/bcm2708_usb/usb1/1-1/1-1.3/1-1.3:1.0/bluetooth/hci0/hci0:39/0005:2810:0009.0021/input/input23
[ 9245.925941] hid-generic 0005:2810:0009.0021: input,hidraw1: BLUETOOTH HID v1.00 Keyboard [8Bitdo SFC30 GamePad] on 99:88:66:00:23:48
# RetroArch = NOT DETECTED. Don't show at all inside RetroArch.
# ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
# dmesg - Lakka - 8Bitdo SFC30-BT(START+R)
# Lakka-RPi.arm-devel-20150529164419-r21027-g43f71a8.img
# 8Bitdo Firmware v2.61 (2015-06-06).
[ 9878.724228] hid-generic 0005:2810:0009.0023: unknown main item tag 0x0
[ 9878.740724] input: 8Bitdo SFC30 GamePad Joystick as /devices/platform/bcm2708_usb/usb1/1-1/1-1.3/1-1.3:1.0/bluetooth/hci0/hci0:39/0005:2810:0009.0023/input/input25
[ 9878.752534] hid-generic 0005:2810:0009.0023: input,hidraw0: BLUETOOTH HID v1.00 Keyboard [8Bitdo SFC30 GamePad Joystick] on 99:88:66:00:23:48
# RetroArch = NOT DETECTED. Don't show at all inside RetroArch.
# ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
# dmesg - Ubuntu - 8Bitdo SFC30-USB
# Ubuntu Linux 3.19.0-21-generic #21~14.04.1-Ubuntu SMP x86_64.
# 8Bitdo Firmware v2.61 (2015-06-06).
[23898.965949] usb 1-4: new full-speed USB device number 18 using xhci_hcd
[23899.094907] usb 1-4: New USB device found, idVendor=1235, idProduct=ab11
[23899.094911] usb 1-4: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[23899.094913] usb 1-4: Product: FC30 Joystick
[23899.094915] usb 1-4: Manufacturer: FC30
[23899.096176] input: FC30 FC30 Joystick as /devices/pci0000:00/0000:00:14.0/usb1/1-4/1-4:1.0/0003:1235:AB11.0022/input/input49
[23899.096314] hid-generic 0003:1235:AB11.0022: input,hidraw1: USB HID v1.10 Joystick [FC30 FC30 Joystick] on usb-0000:00:14.0-4/input0
# RetroArch = OK.
# Autocfg = https://github.com/libretro/retroarch-joypad-autoconfig/blob/master/udev/8Bitdo-SFC30-GamePad-USB.cfg
# ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
# dmesg - Ubuntu - 8Bitdo SFC30-BT(START)
# Ubuntu Linux 3.19.0-21-generic #21~14.04.1-Ubuntu SMP x86_64.
# 8Bitdo Firmware v2.61 (2015-06-06).
[24758.055949] hid-generic 0005:2810:0009.0023: unknown main item tag 0x0
[24758.056069] input: 8Bitdo SFC30 GamePad as /devices/pci0000:00/0000:00:14.0/usb1/1-9/1-9:1.0/bluetooth/hci0/hci0:256/0005:2810:0009.0023/input/input50
[24758.056305] hid-generic 0005:2810:0009.0023: input,hidraw1: BLUETOOTH HID v1.00 Keyboard [8Bitdo SFC30 GamePad] on 28:b2:bd:78:cb:42
# RetroArch = OK.
# Autocfg = https://github.com/libretro/retroarch-joypad-autoconfig/blob/master/udev/8Bitdo-SFC30-GamePad-Bluetooth-Mode(START).cfg
# ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
# dmesg - Ubuntu - 8Bitdo SFC30-BT(START+R)
# Ubuntu Linux 3.19.0-21-generic #21~14.04.1-Ubuntu SMP x86_64.
# 8Bitdo Firmware v2.61 (2015-06-06).
[24891.935505] hid-generic 0005:2810:0009.0024: unknown main item tag 0x0
[24891.935612] input: 8Bitdo SFC30 GamePad Joystick as /devices/pci0000:00/0000:00:14.0/usb1/1-9/1-9:1.0/bluetooth/hci0/hci0:256/0005:2810:0009.0024/input/input51
[24891.936057] hid-generic 0005:2810:0009.0024: input,hidraw1: BLUETOOTH HID v1.00 Keyboard [8Bitdo SFC30 GamePad Joystick] on 28:b2:bd:78:cb:42
# RetroArch = OK.
# Autocfg = https://github.com/libretro/retroarch-joypad-autoconfig/blob/master/udev/8Bitdo-SFC30-GamePad-Bluetooth-Mode(START%2BR).cfg