Ubuntu cross-compile copy to SD doesn't seem to work

[dwhite0]

I am trying to cross compile a new driver into the kernel, and I am running into a problem following the instructions according to:

https://www.raspberrypi.org/documentati ... uilding.md

First, if I do:

sudo make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- INSTALL_MOD_PATH=mnt/ext4 modules_install

I get

make: arm-linux-gnueabihf-gcc: Command not found

So putting the whole path for my compiler in the command line it passes that error. (wasn't a problem for my build- the tools are in my path.

So after that I get:

sudo make ARCH=arm CROSS_COMPILE=/home/dwhite/rpi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/arm-linux-gnueabihf- INSTALL_MOD_PATH=mnt/ext4 modules_install
ln: failed to create symbolic link 'mnt/ext4/lib/modules/4.9.46-v7+/source': Operation not permitted
Makefile:1221: recipe for target '_modinst_' failed
make: *** [_modinst_] Error 1

Any ideas of why the symbolic link can't be created? It creates directories first, then fails.

Thanks in advance.
Darin