There is a lot of online documentation to set up different hats (addon boards) on a RPi2 ... some of them use the serial port and have instructions how to disable the serial console by dropping "console=ttyAMA0" from the cmdline.txt file.
Snappy currently sets the console= options from a uboot var that is set in uboot.env instead:
(RaspberryPi2)ubuntu@localhost:~$ fw_printenv |grep console
mmcargs=setenv bootargs "${args} console=tty0 console=ttyAMA0 root=${mmcroot}"
to drop the serial console option you would have to:
(RaspberryPi2)ubuntu@localhost:~$ sudo fw_setenv mmcargs 'setenv bootargs "${args} console=tty0 root=${mmcroot}"'
(RaspberryPi2)ubuntu@localhost:~$ fw_printenv |grep console
mmcargs=setenv bootargs "${args} console=tty0 root=${mmcroot}"
while this is as easy as editing a text file it will be hard to find for users trying to follow online docs that point to cmdline.txt instead.
all console= options should be moved over to not add confusion over third party documentation.
Ideally, we need to find a *safe* way for the gadget snap to do what's
needed here. We want to avoid any manual editing of files at all. Instead:
* there's a declarative format in the gadget snap which covers
everything needed
* there's some *safe* way for the system to adapt to that declaration