I currently have OpenELEC insalled on my PI and I want to install retropie instead. I do not have a micro sd adapter or reader on my computer. Is it possible for me to install the new operating system over ssh?
Not really. If you have extra space on the card and:
- This space is big enough for retropie.
- You have enough space left in your openELEC root filesystem to download the retropie to.
Then you might be able to:
Create an extra partition.
Copy the contents of the retropie root fs onto the new partition in the card.
Copy the retropie kernel into the boot partition and modify
And you should be able to get retropie to boot, but this would not replace openELEC since it would still be there.
There is another option if you have a linux machine available: booting over nfs. Once you booted over nfs, you are able to modify the root partition/filesystem of your openELEC partition since it is not used so far. You can particularly delete it and replace it with retropie, as goldilocks described in his answer.