See the following steps to get the TI wl18xx drivers to work on the Cubox with the I4P Rev 1.5 SOM.

 

Step 1)
Boot with the Armbian base image (Armbian_5.20_Cubox-i_Ubuntu_xenial_4.7.3).  The 3.14.79 base image also works however will require a different dpkg install command to overwrite the 3.14.79 kernel.

 

Step 2)
Build a new kernel with Armbian build tools, note this only works with the 'DEV' kernel branch because SolidRun provides all the necessary DTS files.

 

Edit the compile.sh script and change KERNEL_CONFIGURE="yes" to customize the kernel configuration.  The relevant modules you will need to select are:

CONFIG_WL_TI=y
CONFIG_WL1251=m (In my last working test I enabled this module but it may not be necessary)
CONFIG_18XX=m
CONFIG_CORE=m
CONFIG_WLCORE_SDIO=m
CONFIG_WILINK_PLATFORM_DATA=y

 

Step 3)
Copy the built kernel deb packages found in output/debs to the Cubox.

linux-dtb-dev-cubox_5.27_armhf.deb
linux-firmware-image-dev-cubox_5.27_armhf.deb
linux-headers-dev-cubox_5.27_armhf.deb
linux-image-dev-cubox_5.27_armhf.deb

 

Note: DO NOT copy the generated linux-u-boot-dev-cubox-i*.deb

 

Step 4)
Install the packages on the cubox;
dpkg -i linux-dtb-dev-cubox_5.27_armhf.deb
dpkg -i linux-firmware-image-dev-cubox_5.27_armhf.deb
dpkg -i linux-headers-dev-cubox_5.27_armhf.deb
dpkg -i linux-image-dev-cubox_5.27_armhf.deb

Update your /etc/network/interfaces file to match your WiFi configuration.

 

Step 5)
Reboot and WiFi should work.
 

Just a follow up, because I spent several iterations tracking this issue down further. If you do install the generated u-boot deb package and reboot, you will most likely see the following error wl1271_sdio: probe of mmc1:0001:2 failed with error -61 in your kernel log.