Enable the following Kernel modules and recompile:
Device Drivers > Network device support > Wireless LAN Marvell 8xxx Libertas WLAN driver support Marvell Libertas 8385/8686/8688 SDIO 802.11b/g cards
Download Binary BLOBs to /lib/firmware:
mkdir /lib/firmware cd /lib/firmware wget wget http://git.kernel.org/cgit/linux/kernel/git/firmware/linux-firmware.git/plain/mrvl/sd8688_helper.bin wget http://git.kernel.org/cgit/linux/kernel/git/firmware/linux-firmware.git/plain/mrvl/sd8688.bin
And reboot. Upon boot, the kernel should try to load the firmware before the rootfs is available and fail.
mmc0: new high speed SDIO card at address 0001 libertas_sdio mmc0:0001:1: Direct firmware load failed with error -2 libertas_sdio mmc0:0001:1: Falling back to user helper
It should then retry after rootfs is available and report something similar to:
libertas_sdio mmc0:0001:1 (unregistered net_device): 00:24:23:1f:b3:e9, fw 10.38.1p25, cap 0x00000303 libertas_sdio mmc0:0001:1 wlan0: Marvell WLAN 802.11 adapter