ok thx it was just that the firmware were in /lib/firmware/mrvl not in the parent folder .

In this file /var/log/kern.log :
Jun 24 15:28:09 sheevaplug-debian kernel: Bluetooth: L2CAP ver 2.14
Jun 24 15:28:09 sheevaplug-debian kernel: Bluetooth: L2CAP socket layer initialized
Jun 24 15:28:09 sheevaplug-debian kernel: Bluetooth: RFCOMM TTY layer initialized
Jun 24 15:28:09 sheevaplug-debian kernel: Bluetooth: RFCOMM socket layer initialized
Jun 24 15:28:09 sheevaplug-debian kernel: Bluetooth: RFCOMM ver 1.11
Jun 24 15:28:10 sheevaplug-debian kernel: Bluetooth: vendor=0x2df, device=0x9105, class=255, fn=2
Jun 24 15:28:10 sheevaplug-debian kernel: btmrvl_sdio mmc0:0001:2: firmware: requesting sd8688_helper.bin
Jun 24 15:28:10 sheevaplug-debian kernel: btmrvl_sdio_download_helper: request_firmware(helper) failed, error code = -2
Jun 24 15:28:10 sheevaplug-debian kernel: btmrvl_sdio_download_fw: Failed to download helper!
Jun 24 15:28:10 sheevaplug-debian kernel: btmrvl_sdio_probe: Downloading firmware failed!

In the folder /lib/firmware/mrvl : i have helper_sd.bin  sd8688_ap.bin  sd8688.bin  sd8688_helper.bin
What does mean the error code 2 ?
Is possible that the kernel can't do the link with the firmware ?

Hello,
I have a guruplug server, i want to use pan in order to use internet connexion by bluetooth thanks a bridge between bluetooth and ethernet on guruplug. First with hcitool dev i can see the chip bluetooth with information (MAC ...) After i compiled the source of bluez and i try to configure the bridge. But now with hcitool dev i have nothing. I unistall all bluez package but i think they overwrite some config file but i dont know which. So i want to return to the default config, at least i want to see bluetooth chip info again. How can i do ? I precise i don't have a jtag.
Thank for helping me.