Bypass USB mass storage and USB networking

Normally when the cloud9 image boots on beaglebone, it starts a USB mass storage driver (near the end of bootup) which causes the fat32 partition of the SD card to show up in Windows Explorer if you’re connected to a Windows machine. Then if you click ‘eject’, it stops that driver and starts a USB ethernet driver and DHCP server.

Well I want to bypass all that. I just want to use the micro-USB port as a serial console, nothing else. I’m trying to figure out where in the systemd start-up scripts to disable all that. I have found the following related files in /lib/systemd/system:
storage-gadget-init.service

network-gadget-init.service

udhcpd.service

And this link in /lib/systemd/system/basic.target.wants:

storage-gadget-init.service → …/storage-gadget-init.service

I tried removing these files, I tried editing them to do something else, but the USB mass storage driver keeps trying to start, which is causing me problems.

Any ideas?