Read-only file system - Rookie Mistake?

Hi all,

Having previously written several apps for my LG TV, I now have a Raspberry Pi 4 onto which I have installed WebOS OSE 2.28. Everything's been going well so far, connected up to network, confirmed IP address, testing SSHing in remotely, all good. I've created my first OSE app and am attempting to deploy it however here's where things fall down.

In VS Code, if I try to deploy using the extension I get an error saying that the file system is read-only. SSHing in and trying to create a folder I can see that that's the case too.

root@raspberrypi4-64:/# cd media
root@raspberrypi4-64:/media# mkdir developer
mkdir: can't create directory 'developer': Read-only file system

Have I missed something in setup?

I've tried with both webos-image-raspberrypi4-64.wic and webos-image-devel-raspberrypi4-64.wic

Thanks,

Jimmy