I have had a play with filling the disk and doing a sync. Unfortunately, it doesn't seem to work to prevent the download and installation of an update, but still allow syncing. I have played with leaving various amounts of free space, but, none seem to do what is desired.
Just in case someone wants to try, I have posted a test version of the
Kobo Utilities plugin. This has an extra option on the menu called "Fill disk". This allows you to set an amount of free space to leave and then creates a file to fill the disk.
My testing has been on two different Touch's. One has 2.5.2 and the other 3.1.1. I haven't tried the Glo as I didn't feel like setting it back from 3.2.0.
My conclusions from this testing are that if an update is found during a sync:
- If there is not enough space to download the firmware update file, you will get a not enough space error and the download won't happen.
- If there is not enough space to download the update and unpack it, the file will be downloaded, but an error is displayed afterwards. The downloaded file is removed on 3.1.1 but not on 2.5.2.
- If there is enough space to download the update and unpack it, the file will be downloaded, unpacked and you get prompted to install it.
For none of the cases was the sync done.
There is also a minimum free space below which a sync won't be done. In this case, a not enough space message is displayed. I didn't test at what free space this happened at, but I suspect it is 50MB.
The test version of the plugin is there if someone wants to try and confirm, or better still, disprove my conclusions. Or check them on another device or firmware level. I recommend doing it while you have something else to do as each test takes time. Watching "Aliens" again was a suitable distraction.